論文
公開件数:278件
No. 掲載種別 単著・共著区分 タイトル 著者 誌名 出版者 巻号頁 出版日 ISSN DOI URL 概要
1 研究論文(学術雑誌)
共著
A Numerical Model for Denitrification of Municipal Landfill Leachate and Parametric Analysis on Denitrification Controlling Factors
K.Michioku, K.Tanaka, H.Tanaka, K.Inoue, T.Nakamichi, M.Yagi and N.Wada
WIT Trasnsaction on Ecology and Environment
WIT Press
231, 327-328
2018/09/18
1743-3541



2 研究論文(国際会議プロシーディングス)
共著
Performance of a groyne in controlling flow, sediment and morphology around a tributary confluence
K.Michioku, Y.Osawa and K.Kanda
Proc. 9th Intnl. Conf. on Fluvial Hydraulics, RIVER FLOW 2018
EDP Sciences
E3S Web of Conferences 40, 040, 1-8
2018/09/05

10.1051/e3sconf/20184004006
URL
In a middle stream reach, irreversible morphological changes are observed such as growth of a huge sandbar in front of the confluence, thalweg migration from the left to right bank, erosion of the main channel and sedimentary deposit on the floodplain. As a countermeasure against such degradation of river morphology, a groyne was constructed beneath the tributary confluence. Performance of a groyne in controlling flood flow, sediment transport and river morphology was investigated by a two-dimensional hydrodynamic model. The analysis on twenty years of morphological change indicates that the groyne has an excellent performance in improving quality of river morphology such as reduction of the sandbar development and migration of the thalweg to the original position.
3 研究論文(学術雑誌)
共著
An Experiment on Simultaneous Operation of Nitrification and Denitrification of Municipal Landfill Leachate in A Single Reaction Tank
K.Michioku, K.Tanaka, H.Tanaka, K.Inoue, T.Nakamichi, M.Yagi and N.Wada
WIT Transaction on Ecology and Environment
Wessex Institute of Technology
228, 131-143
2018/05/22
1743-3541


Leachate from municipal disposal landfill brings a significant load of ammonia in receiving waters. Since phosphorus and degradable organic carbon are mostly filtered out from the leachate in the course of subsurface runoff, conventional treatment technology such as activated sludge process is not available for nitrogen removal from the leachate. The authors are developing a new biological technology of low-cost leachate treatment which consists of nitrification with micro-bubble (MB) aeration and denitrification by using fatty acid compounds, FAC. Laboratory experiments showed that denitrification was in progress even in an aerobic reactor, when carriers coated with FAC were equipped in the aeration tank. The result indicates that both the nitrification and denitrification simultaneously occurred in a single reaction tank, which suggest there is the possibility to devise an economically feasible treatment system with a very simple structure.
4 研究論文(学術雑誌)
単著
分取水工の三次元ポテンシャル流解析
道奥康治
土木学会論文集B1(水工学)
土木学会
73/ 3, 71-76
2017/10/20



開水路の分取水工近傍に形成される縮流や局所洗堀などを制御するためには,三次元水理解析に基づいて呑口の形状・諸元を適切に設定する必要がある.このように流線が収歛する流れでは空間的な加速領域が形成されて慣性項が卓越するため,条件によっては完全流体近似が可能である.本研究では,主水路側面から直角に分取水される流況を想定し三次元ポテンシャル流の理論解を求める.運動方程式が不在のため,動水勾配や乱流・粘性などが卓越する流況への適用には限界があるが,主水路・呑口の様々な諸元・幾何条件に対する三次元分取水流の厳密解が机上計算により簡易に得られる.本理論を予備解析ツールとして利用すれば,動力学を考慮した三次元数値解析や水理模型実験を実施するための解析条件を絞り込むなど,水理設計の省力化を実現できる.
5 研究論文(その他学術会議資料等)
共著
持続可能な国土をめざす知の基盤形成-「国土学」の体系と戦略的実践
道奥康治他(国土と環境分科会)
第23期提言
日本学術会議
1-16
2017/09/29


URL
環境と災害への一体的対応を基軸とする国土形成を支えうる学術分野の重要課題を抽出し、新たな知の体系である「国土学」を提案するとともに、社会実装のための人材育成システムと学術運営の戦略と方策のあり方を提唱する。
6 研究論文(学術雑誌)
共著
上流の河道形状と堰湛水の影響を受ける合流部の河床変動とその制御に関する研究
髙田翔也・神田佳一・道奥康治・久保裕基・岡本吉弘
土木学会論文集B1(水工学)
土木学会
73/ 4, I_865-I-870
2017/02/01



兵庫県を流れる加古川では, 加古川大堰の上流区間において, 堰の湛水と左支川美嚢川の合流,及び上流河道の弯曲の影響により, 合流部での右岸砂州の肥大化や澪筋の左岸への偏向・固定化, 水面利用域の浅水化が進行している.本研究では,美嚢川合流部周辺の河川地形とその形成要因に関して,現地河道を模した合流模型実験水路を用いて移動床実験を行い,合流部での流れと河床形状を支配する要因を明らかにするとともに,砂州の制御の為に設置された水制工の水理機能とその効果について,移動床模型実験により考察した. また,2次元流れの公開数値解析ソフトNays2DHを用いて実験の再現計算を行い, 実験結果の検証とその適用性の検討を行った.
7 研究論文(国際会議プロシーディングス)
単著
Towards A Comprehensive Design of Nature-Oriented River Structures
Kohji Michioku
Proc. 7th Civil Engineers Conference in the Asian Region
ASCE
CD-ROM, 1-12
2016/08/31



Along the paradigm of near-nature river work, structures tend to be constructed with natural materials such as stones, boulders, logs, timbers, live trees, branches, rootwads and so on. In order to diffuse the nature-oriented structures to more river restoration projects as state of the arts technology, it is required to understand the complex interrelating system between hydrodynamics, fluvial process and ecosystem around structures. The present article is to highlight recent research works focusing on hydrodynamics of natural vegetation- or rock-arranged structures. First, traditional river structures such as flood protection forests, weirs, groynes, spurs, rough ramps are overviewed. Secondly, some examples of hydraulic models for analyzing the vegetated channel's hydrodynamics are reviewed, anticipating that the riparian vegetation would be used as shore protection works. Thirdly, hydrodynamics are discussed for rock-arranged structures such as dykes, embankments, weirs, spurs, groynes, ripraps, ramps, fish ladders and so on. Fundamental researches on hydraulic conductivity and flow drags of rock-fill structures are briefly reviewed and analyses on flow fields around the structures and structure failures are shown.
8 研究論文(国際会議プロシーディングス)
共著
Field measurement and numerical analysis on tree breakage modes during floods in a middle-stream reach
K. Michioku, K. Kanda, S. Kometani, Y. Irie
Proc. RIVER FLOW 2016
TAYLOR and FRANCIS GROUP, LONDON, UK, CRC Press
1860-1868
2016/07/12
978-1-138-02913-2


Two types of breakage or dislodgement mode are observed in riparian vegetation after flood, i.e. (I) overturn-ing and (II) uprooting, which have distinctly different breakage mechanisms from each other. The overturn-ing is driven by the drag force moment, while the uprooting is caused by local scouring of substrate layer around a trunk. Therefore, the breakage mode is determined by local flow structure, vegetation characteris-tics and properties of bed materials. In order to examine tree breakage situations after a flood event, field measurements were carried out in a middle-stream reach where willows were densely vegetated on the flood-plain. The observed breakage mode was classified into four categories; (A) unbroken, (B) overturned, (C) uprooted, and (D) overturned and uprooted. A hydrodynamic analysis of flow and drag force during flood was performed by using a two-dimensional two-layer (2D2L) hydrodynamic model in which the system was vertically segregated into the vegetation and overlying water layers by an interface that encompasses the vege-tation canopy. In order to verify the analysis, the tree breakage mode estimated from the model was com-pared with the field data and agreement between the analysis and measurements was confirmed.
9 研究論文(国際会議プロシーディングス)
共著
Optimization of nitrification/denitrification process in landfill leachate treatment
Kohji MICHIOKU, Hiroaki TANIURA and Kosuke INOUE
Proc. 11th International Symposium on Ecohydraulics 2016

1-8
2016/02/08



A nitrification/denitrification system was proposed for treatment of leachate from a municipal solid waste landfill. The system consists of ammonia oxidization by using a "Micro-Bubble" (MB) aeration and denitrification with the aid of fatty acid compounds (FAC). A water quality model was devised to describe hydraulic and biological behaviors of the relating substances. Assuming a biochemically equilibrium state, solutions for nitrification and denitrification rates and concentration of each nitrogen component are obtained for a given operating condition such as leachate loading rate, MB aeration discharge and amount of FAC. An operating condition for achieving the highest performance of nitrogen removal was proposed based on the water quality model.
10 研究論文(国際会議プロシーディングス)
共著
Manning's coefficient of alternatively arranged sandbars with tree vegetation
K. Kanda, S. Kometani, Y. Irie and C. Sakamoto
E-proceedings of the 36th IAHR World Congress
28 June – 3 July, 2015, The Hague, the Netherlands

1-12
2015/06



Recently, many river channels tend to be densely vegetated due to regime shifts in hydrological, fluvial and ecological processes. It is a critical engineering issue for flood control and management to evaluate the conveyance capacity of vegetated channels. In this study, an equivalent Manning’s coefficient nv of vegetation canopy drag in an open channel of compound cross section with alternatively arranged floodplain is analyzed by using a two-dimensional two-layer (2D2L) model. It is found that nv monotonically increases with increasing discharge when vegetation is emerged. On the other hand, nv gradually decreases with discharge in the case of submergent vegetation. The numerical solutions of flow structure and nv is compared with experimental data to verify the model and satisfactory agreement between the analysis and the experiment is recognized.
11 研究論文(大学,研究機関紀要)
共著
都市ゴミ埋立地から浸出する汚染水の脱窒処理に関する水質モデルと制御因子の分析
田中健治,田中大也,井上晃介,中道民広,八木正博,和田有朗
都市安全研究センター研究報告

19, 200-209
2015/03



都市ゴミ埋立地浸出水の窒素負荷を軽減するため,水素徐放剤を利用した脱窒技術を実験的・理論的に検討した.浸出水には脱窒に必要な炭素源が不足しているため,現在はメタノール添加による処理工程が組まれている.しかし,まもなく閉鎖を予定している排水処理施設に代わる処理系は現行よりも簡素で省力的でなければならない.そこで,浸透性反応層の炭素素材として水素徐放剤の利用を目指し,各種炭素源やリンなどの添加剤,担体,浸出水負荷量など各種支配因子が脱窒効率に及ぼす影響を水質モデルにより検討した.水質モデルは著者らの室内実験で計測された脱窒過程を精度よく再現し,水理学的滞留時間(HRT)などの処理条件が脱窒に及ぼす影響が定量的に評価された.
12 研究論文(大学,研究機関紀要)
共著
浸出水貯留池におけるマイクロバブル硝化のエンクロージャー実験と水質解析
田中健治,井上晃介,田中大也,中道民広,八木正博,和田有朗
都市安全研究センター研究報告

19, 192-199
2015/03



1970-80年代に都市ゴミを埋め立てた処分場から,現在もなお,高濃度のアンモニア態窒素を含む汚染水が浸出している.浸出水は嫌気的であり生物化学的な窒素除去工程の第一段階は硝化である.浸出水負荷の突発的変動に追随可能で,かつ効率的な窒素除去を目指し,マイクロバブル技術を用いた浸出水貯留池の曝気・硝化を実施した.曝気量,浸出水負荷流量,担体量,反応槽容量などの条件が硝化効率に及ぼす影響を明らかにするために,貯留池内にエンクロージャー(隔離水塊)を設置し,曝気にともなう水質挙動を計測した.また,硝化菌の消長,溶存酸素・窒素・有機物収支などを考慮した水質モデルによって浸出水の硝化特性を再現し,硝化効率に及ぼす制御諸因子の影響を定量的に評価した.
13 研究論文(大学,研究機関紀要)
共著
廃棄物埋立地浸出水の単一反応槽内での硝化・脱窒同時処理に関する実験的検討
田中健治,田中大也,井上晃介,中道民広,八木正博,和田有朗
都市安全研究センター研究報告

19, 183-191
2015/03



都市ゴミ埋立地から浸出する汚染水は,地中を透過するため,アンモニア態窒素を高濃度に含み嫌気的である.脱窒に必要な素材である易分解性有機物やリンは枯渇しており,一般下水と同様の窒素除去技術を適用することは難しい.省力的・持続的な窒素除去を実現するために,マイクロバブル曝気による硝化と水素徐放剤を炭素源とする脱窒処理の実験を行った.その結果,反応槽が曝気によって好気的に維持されていても,水素徐放剤を塗布した担体の基質表面に脱窒菌を含む嫌気的な微生物膜が形成され,硝化と脱窒が同時に進行することを確認した.溶存酸素の供給・消費を分析し,硝化・脱窒の同時進行に果たす酸素条件や水素徐放剤などの炭素源,リンの役割を明らかにした.
14 (MISC)その他記事
単著


土木学会論文集 B1(水工学)

71/ 4, CD-ROM
2015/02



水工学をとりまく状況と研究の現状を総括するとともに水工学委員会の諸活動を紹介した。また、水工学論文集第59巻の編集について委員会を代表して報告した。
15 研究論文(学術雑誌)
共著
再利用資源を代替炭素源とする浸出水の脱窒技術の実験的検討
井上晃介・黒田將嵩・中道民広・八木正博
土木学会論文集 B1(水工学)

71/ 4, I_763-768
2015/02

10.2208/jscejhe.71.I_763

In order to develop an alternative denitrification system for purification of leachate from a municipal waste landfill, a laboratory experiment was carried out. Denitrification performance using alternative carbon resources in place of methanol was experimentally investigated in a laboratory tank. The carbon sources under investigation were hydrogen feeding agents, beer lees and solidified food oil. Hydrogen feeding agents and solidified food oil showed higher denitrification performance than the beer lees. The water quality model was verified by comparing the analytical solutions with the laboratory data using hydrogen feeding agents as carbon source. Time-dependent behaviors of every water quality component observed in the experiment were very well reproduced by the model. The analysis showed that the hydrogen feeding agent was found to be a very promising material for efficiently removing nitrogen from seriously contaminated leachate.
16 研究論文(学術雑誌)
共著
樹木粗度を有する交互砂州地形の相当粗度
米谷駿一・神田佳一・入江良幸・坂本知奈美
土木学会論文集 B1(水工学)

71/ 4, I_763-768
2015/02

10.2208/jscejhe.71.I_631

Recently, many river channels tend to be densely vegetated due to regime shifts in hydrological, fluvial and ecological processes and it is a critical engineering issue to evaluate conveyance capacity of vegetated channels. Although drag force coefficient is popularly used in evaluating drag force of vegetation, it is not always a convenient parameter in determining high water level, HWL, for a design flood. In this study, an equivalent Manning’s coefficient nv, which corresponds to drag force of overgrown vegetation in alternative bars, was theoretically evaluated by the two-dimensional two-layer (2D2L) hydrodynamic model. It was found that nv monotonically increases with increasing discharge as long as vegetation emerged. On the other hand, nv slightly decrease with discharge after vegetation submerged. Findings is to provide useful information for flood management of vegetated river channel.
17 (MISC)会議報告等
共著
国民生活を強大化する水害からまもるために,座談会「まもる:防災と環境保全」
佐藤孝洋・金尾健司・中尾高志・矢野真一郎
土木学会誌

99/ 11, 1-6
2014/11



温暖化の影響や異常気象など,強大化が予想される水害から国民の生命と財産を「まもる」ために求められる対応とは何なのか.水工学分野,救助活動専門家,国と自治体の河川行政担当者の方々に,これまでの河川行政を振り返り,自助・共助など今後市民に求められる対応に触れながら,議論頂いた.
18 研究論文(学術雑誌)
共著
Experimental and numerical study on hydrodynamics of riparian vegetation
Uotani,T, K. Kanda
J. Hydrodynamics, Ser. B

26796-806/ 5
2014/10
1001-6058
10.1016/S1001-6058(14)60088-3

Recently, many channelized rivers tend to be heavily vegetated due to regime shifts in hydrological, fluvial and ecological processes. Dense vegetation in a river frequently obstructs a flood flow and reduces conveyance capacity of channels. On the other hand, river vegetation provides various ecological services such as habitats for various species and life, natural cycle of organic and inorganic substances, etc‥ It is of engineering importance to understand vegetation hydrodynamics in order to preserve vegetation nature and keep a certain level of flow conveyance capacity. In view that willows tend to be densely vegetated along the shoreline of floodplains or sandbars, a field measurement, a physical model experiment and a numerical analysis were carried out for investigating hydrodynamics in an open channel with riparian vegetation. Discussion was made focusing on flow and shear layer structures developed around the vegetation canopy.
19 研究論文(国際会議プロシーディングス)
共著
Analysis on historical changes in river morphology influenced by barrage construction and tributary confluence
T.Okuyama, K.Michioku, K.Kanda ans S.Kometani
ICHE 2014, Hamburg - Lehfeldt & Kopmann (eds)

633-641
2014/09
978-3-939230-32-8


The topic in this study is river morphological changes in the last two and a half decades since barrage con-struction. The major impacts imposed on morpho- and hydrodynamics in this reach are reservoir for-mation behind the barrage and confluence of a major tributary. They have caused significant regime shifts in morphodynamics and ecosystem such as development of an island in front of the tributary con-fluence, thalweg migration from the left to right bank around the confluence, vegetation overgrowth on emergent sandbars, erosion of the main channel and sedimentary deposit on the floodplain, loss of spawn-ing habitat for sweetfish, water depth decrease in the area of regatta course and so on. In order to exam-ine the mechanism of the historical changes in river morphology, a numerical analysis on hydrodynamic and sedimentation processes was carried out by using an open source software, the "iRIC". Characteris-tic geomorphological features mentioned above were well reproduced by the present analysis. Influence of the two major impacts, i.e. barrage impoundment and tributary confluence, on river morphodynamics was discussed by performing a response analysis under two scenarios: no barrage and no tributary conflu-ence.
20 研究論文(国際会議プロシーディングス)
共著
Analysis of equivalent Manning’s roughness coefficient for trees vegetated on floodplain
S. Kometani, T. Uotani, K. Kanda, Y. Irie & K. Yanagida
Proc.Int.Conf.Flluvial Hydraulics (RIVER FLOW 2014)

563-570
2014/09/05
978-1-138-02674-2


The high water level, HWL, for a design flood is the most important parameter in flood control and manage-ment. It is a critical issue how to determine Manning’s roughness coefficient in vegetated reach, since chan-nelized rivers tend to be densely vegetated during previous decades. Although there are several sophisticat-ed numerical models to analyze the flow structure in vegetated channels, flow resistance due to vegetation is usually formulated in terms of a drag coefficient which is not always a convenient parameter in determining HWL in a flood control design. HWL is usually analyzed by a one dimensional non-uniform flow model in which Manning’s coefficient is required in describing channel perimeter’s roughness such as vegetation. In this study, Manning’s coefficient nv for canopy drag was theoretically estimated by using a two-dimensional two-layer (2D2L) hydrodynamic model that was developed by the authors. The model’s performance was already confirmed in laboratory and field experiments. A functional dependency of nv on vegetation proper-ties such as vegetation structure, stem diameter and height of vegetation, etc. was investigated. In the case of emergent vegetation, nv increases with increasing discharge, since flow blockage due to vegetation propor-tionally increases with water depth. On the other hand, nv takes approximately a constant value inde-pendently of water depth and discharge in the case of submergent vegetation, which is one of characteristic findings in the present study.
21 研究論文(学術雑誌)
共著
支川合流の影響を受ける大堰湛水区間における河川地形の経年変化解析
奥山貴也・神田佳一・米谷駿一
河川技術論文集

20, 307-312
2014/06



The topic in this study is river morphological changes in the last two and half decades after a barrage construction. The major impacts imposed on morpho- and hydrodynamics in this reach are formation of the reservoir by the barrage and confluence of a major tributary, which have caused significant regime shits such as formation of an island in front of the tributary confluence, main channel migration from the left to right bank around the confluence, vegetation overgrowth on emergent sandbars, erosion of the main channel and deposition on the floodplain, loss of spawning habitat for sweetfish, water depth decrease in the area of regatta course and other issues, etc. In order to examine the mechanism of the historical changes in river morphology, a numerical analysis on hydrodynamic and sedimentation processes was carried out by using an open source software, the "iRIC". Characteristic geomorphological features such as formation of an island at the tributary confluence and an emerged sandbar development at the left bank side are well reproduced by the present analysis. Influence of the two major impacts, i.e. reservoir formation and tributary confluence, was discussed by performing a response analysis under two scenarios that are in the absence of the reservoir and tributary.
22 (MISC)総説・解説(学術雑誌)
単著
四半世紀における水工学小史

混相流

28/ 1, 1-2
2014/03/15
0914-2843


4半世紀にわたる水工学の歩み,特に混相流研究が果たした水工学分野での貢献と今後の課題を示した.また,水工学を含む学術研究と大学教育の現状を総括した.
23 (MISC)会議報告等
単著


土木学会論文集 B1(水工学)

70/ 4, CD-ROM
2014/02/27



水工学をとりまく状況と研究の現状を総括するとともに水工学委員会の諸活動を紹介した。また、水工学論文集第58巻の編集について委員会を代表して報告した。
24 研究論文(学術雑誌)
共著
高水敷水際の樹林帯が複断面開水路の水理特性におよぼす影響
魚谷拓矢・神田佳一
土木学会論文集 B1(水工学)

70/ 4, I_715-720
2014/02/27

10.2208/jscejhe.70.I_715

Willows are one of the most predominant species vegetated in many channelized rives. Willows tend to sprout and grow mostly along shoreline of the main channel. Since the riparian zone is exposed to river flow, willows vegetated there could be frequently destructed by flood flows depending on channel's geomorphology and flood frequency. If a river restoration would be properly carried out, overgrowth of riparian willows could be efficiently controlled and minimized by using natural flow forces. Therefore, it is a key issue to understand hydrodynamics of riparian willows for a labor-saving river management. In this study, a numerical analysis and laboratory experiment were performed in order to examine hydrodynamics of an open channel with compound cross section vegetated along shoreline.
25 研究論文(学術雑誌)
共著
河川敷上の樹木に作用する流体抗力解析とその検証
谷口麻衣・魚谷拓矢・阿河一穂・神田佳一
土木学会論文集 B1(水工学)

70/ 4, I_1357-1362
2014/02/27

10.2208/jscejhe.70.I_1357

From technological and ecological viewpoints, it is a critical issue to control overgrowth of trees vegetated in floodplains. The authors have developed a hydraulic model which is able to describe flow and drag force in vegetated channels. The model has a two-layer structure in order to analyze both the slow flow through the vegetation and the fast flow over and besides the vegetation. The model was
already confirmed to have a satisfactory reproducibility of flood flow structure through the authors' previous studies. In the present study, by collecting additional field data of trees and flood events, the model’s performance in identifying areas and amounts of destructed trees was verified. The model could be a useful engineering tool for making a proper ecological management of tree vegetation and
channel restoration projects.
26 研究論文(学術雑誌)
共著
複断面開水路における樹林の流水抵抗に関する相当粗度係数
米谷駿一・魚谷拓矢・神田佳一・入江良幸・柳田昂希
土木学会論文集 B1(水工学)

70/ 4, I_697-702
2014/02/27

10.2208/jscejhe.70.I_697

The high water level, HWL. for a design flood is the most important parameter in flood control and management. It is a critical issue how to determine Manning roughness coefficient in a vegetated reach, since channelized rivers tend to be densely vegetated in last decades. Although there are several sophisticated hydrodynamic models to analyze flows in vegetated channels, flow resistance due to
vegetation is usually formulated in terms of a drag force coefficient which is not always a convenient parameter in flood control management. The HWL. is usually determined from a one dimensional nonuniform flow analysis in which Manning roughness coefficient is required in describing channel perimeter’s roughness such as vegetation. In this study, an equivalent Manning roughness coefficient, nv, for a vegetated reach was theoretically estimated by using a two-dimensional two-layer (2D2L) flow model that was developed by the authors. The model’s performance was already confirmed by laboratory and field experiments. A functional dependency of nv on vegetation properties such as
discharge, profiles of vegetation, stem diameter, tree height, etc. was investigated. It was found that nv was kept constant independently of water depth or discharge after the vegetation being submerged.
27 (MISC)速報,短報,研究ノート等(大学,研究機関紀要)
単著
河川中流域における緑化進行と治水・環境上の課題

神戸大学環境報告書

2013
2013/09/01



川の橋梁を横断すると,ほとんどの川面は草木に埋まり,緑豊かな景色に変わっている.「緑豊かな川」をよい自然環境と勘違いしてはならつならず,洪水時には,樹木が流れの抵抗体となり,樹林から発生した流木は橋脚に引っ掛かって流れを阻害し越水氾濫をもたらす.樹木が繁茂すると水辺に近づいて親水活動を楽しむことはできない.多様な生物のハビタート(「生息・生育空間」のこと)であった緩勾配の岸辺は失われ,草木の種数は減少して単調な植生系が形成される.鳥類は食物連鎖の高次捕食者で生態系に大きく影響する生物であるが,河川には生息していなかったはずの鳥類が,樹木に営巣し生態系全体のバランスが崩れる.河川の緑化がもたらす治水面・環境面での河川機能の低下を示し,樹林化した河川の水理学的研究の現況を紹介した.
28 研究論文(国際会議プロシーディングス)
共著
Aeration strategy to minimize deoxygenation in reservoir metalimnion
H. Kotani
Proc. 35th IAHR World Congress

CD-ROM
2013/09/01



Metalimnion became anoxic in a eutrophic reservoir during the warm season, although the hypolimnion became successfully aerobic by an aeration system. Since drinking water is withdrawn from the anoxic metalimnion, the performance of the water purification plant has recently
declined. The three types of aeration systems, (i) air diffuser system, (ii) air bubbler destratification system and (iii) air bubble jet system, were evaluated for their performance as countermeasures against deoxygenation of the reservoir metalimnion. In the water quality model, physical processes such as dissolved oxygen dilution and vertical mixing caused by aeration were taken into consideration in
addition to hydrodynamics and biochemical processes regarding to water quality. After the model was verified through a comparison with the field data, the water purification performance was investigated for the three types of aeration systems with various capacities. In this study, difference of dissolved oxygen concentration before and after the aeration was taken as an indicator of aeration performance. Furthermore, in order to analyze the cost performance of the system in addition to the mechanical
performance, cost benefit was measured by the variable considering the initial and running costs of each aeration system. The air bubbler destratification system was found to have the highest cost benefit performance among the three.
29 研究論文(国際会議プロシーディングス)
共著
Hydrodynamic influence of vegetated floodplain morphology on drag force moment acting on trees
M. Taniguchi, K. Aga, and K.Kanda
Proc. 35th IAHR World Congress

CD-ROM
2013/09/01



In order to investigate how vegetated floodplain affects flow drag force on trees, a field survey and hydrodynamic  nalysis were performed in a vegetated river channel. A hydrodynamic analysis was conducted by a two-dimensional two-layer (2D2L) flow model that can analyze a wide range of water level and vegetated height. A field measurement was carried out in order to examine tree destructed behaviors during flood events, which was compared with the analytical solution of drag force. The observed locations of destructed trees were well correlated with the areas where a significant drag force moment was numerically estimated to occur. The model was additionally applied for discussing river and forest management strategies that could most efficiently promote flooding on the vegetated floodplain to destruct the trees. Taking tree growth rate into consideration, several scenarios for forest felling and floodplain excavation were assumed to evaluate the tree destruction probability under a flood event with a certain return period. It was found from the analysis that floodplain excavation and thinning and felling of trees could promote tree destruction due to flood flows.
30 研究論文(国際会議プロシーディングス)
共著
Experimental and numerical study on hydrodynamics of riparian vegetation
T. Uotani, K. Kanda
Proc. 35th IAHR World Congress

CD-ROM
2013/09/01



Recently, many river channels in Japan tend to be heavily vegetated due to regime shifts in hydrological, fluvial and ecological processes. Dense vegetation on floodplains and sandbars frequently obstructs a flood flow and reduces channels' conveyance capacity. On the other hand, it is important from an environmental viewpoint to make a proper management of riverine vegetation, because trees and plants provide habitats for various species and life. They play an important role as a part of the river ecosystem. In order to preserve trees nature and keep a certain level of flow conveyance capacity, thinning and felling of riverine trees might be one of possible management strategies for a sustainable and economically feasible river management. In order to investigate effects of tree thinning on river hydrodynamics, a laboratory model experiments was carried out in a compound open channel with riparian vegetation, which is a typical ecological structure frequently observed in many rivers. Hydrodynamics were experimentally and analytically investigated under various vegetation and hydraulic conditions.
31 研究論文(国際会議プロシーディングス)
共著
A field experiment and water quality modeling on nitrification of waste landfill leachate by using micro-bubble aeration
K. Inoue, K. Tanaka, H. Tanaka, M. Yagi and T. Nakamichi
Proc. 35th IAHR World Congress

CD-ROM
2013/09/01



Significant ammonia nitrogen is loaded from a municipal landfill leachate. Since the leachate is deoxidized through infiltration and travelling underground, the first step of water treatment is to oxidize or nitrify the leachate. Although various nitrification techniques have been developed so far, such concentrated treatment systems are feasible only in a case of young landfill with an extremely high level of ammonia load. The landfill in this study is, however, already older than forty years and ammonia-nitrogen load has decreased to a level around several ten mg per liter. In this case, a labor-saving and economic nitrification system is required for making a sustainable water quality management. In a leachate reservoir under investigation, a micro-bubble aeration system was equipped
and its nitrification performance was examined by conducting an in-situ experiment in an enclosure. Monitoring time-dependent behaviors of NH4+-N, NO2--N, NO3--N and DO, it was discussed how the nitrification rate was influenced by relating limiting factors. It was also confirmed that denitrification took place in addition to nitrification in the experimental system. It is shown that the micro-bubble aeration is a promising technology as an alternative of the present water treatment system.
32 (MISC)会議報告等
共著
第62回 理論応用力学講演会"NCTAM"の報告 (混相流に関するオーガナイズド・セッション)
大川富雄・村井祐一
混相流

27/ 2, 191-194
2013/06/01



日本混相流学会の発足母体である日本学術会議との連携を強化するために理論応用力学講演会の幹事学会としてオーガナイズドセッションを企画・運営した.
33 研究論文(国際会議プロシーディングス)
共著
Hydrodynamics and hydromorphology of river structures constructed by natural materials
M. Nanjo, M. Haneda, K. Kanda and Z. Li
Proc. 6th Intnl. Conf. Water Resources and Environment Research, Water & Environment Dynamics


2013/06/01

10.5675/ICWRER_2013

The ecological quality of many channelized rivers has degraded in the past few decades. The paradigm has shifted in the direction of near-nature river work. Natural materials such as sand, stones, boulders, logs, woods and vegetation are widely used for construction of river structures. However, discussion has been made only qualitatively or empirically on their performance in controlling hydrau-lic and fluvial processes. In this study, attention is paid on hydrodynamics and hydromorphology, especially of weir, groyne and riparian constructed by rubbles, natural stones and vegetation, and their characteristics are quantitatively evalu-ated by using an experimental and a numerical model. Common hydrodynamic features found in this type of structures are permeability, solid-liquid phase flows, mass-momentum exchange within and outside of the structure, etc., which are taken into account in the numerical model. This study will discuss how the model would be applied as an engineering tool for planning and designing sustainable and nature-friendly river structures.
34 研究論文(国際会議プロシーディングス)
共著
Impact of river morphological changes on floodplain vegetation
Aga H., K. Kanda and T.Uotani
Proc. 10th Intnl. Conf. HydroScience and Eng.

CD-ROM, 10 pages
2012/11



Forestation and vegetation overgrowth on floodplains are worldwide issues from a river engineering standpoint. The study field is a reach of about 30km in length from the river mouth where the discharge is not controlled by facilities. Based on data analysis of the river morphology, hydrology and land cover in the last few decades, the main cause of floodplain forestation was found to be decreased frequency of floodplain inundation after consecutive channel restoration works. In order to evaluate historical changes in the frequency of floodplain inundation and drag force moment acting on trees, a hydrodynamic analysis of vegetated channel was carried out at six cross-sections from middle to downstream. Investigation was performed on how floodplain excavation and thinning of tree vegetation modify flow structure and tree destruction during flood events. Discussion is based upon the analysis of what a proper management strategy would be in order to minimize vegetation growth as well as to create a safe and attractive riverfront. The result provides a direction for a labor-saving and sustainable management strategy for vegetated channels.
35 研究論文(国際会議プロシーディングス)
共著
An experimental study on denitrification of leachate continuously loaded from a municipal waste landfill
K.Tanaka, M.Yagi, T.Nakamichi and N.Wada
Proc. Intnl. Groundwater Sympo. 2012

297-305
2012/11



A laboratory experiment on denitrification was carried out in order to develop a technology for treatment of leachate from municipal waste landfill. The authors have already collected fundamental data from a preliminary experiment on denitrification in a closed test tank. The present experiment was performed in a circulating test tank with leachate loading similar to the prototype. Investigation was
performed to determine how parameters, such as decomposable organic compounds, phosphorus, denitrifiers and nitrogen loading rate, affected denitrification performance. A functional dependency of denitrification rate on the hydraulic retention time obtained from the experiment provides information useful for developing and planning a treatment plant.
36 (MISC)総説・解説(学術雑誌)
単著
水工学諸問題における混相流科学の視点

混相流

26/ 3, 273-284
2012/09



A paradigm for river management was shifted after a legal reform of the river act in 1997, where preservation and mitigation of natural environment became an essential engineering issue in addition to flood control and water use. After then, multi-phase flow researches in river engineering have tremendously changed their direction from hydrodynamics to ecohydraulics that is an integrated engineering disciplines consisting of hydraulics, ecology and biochemistry. Hydraulic engineers are required to develop engineering management tools of river ecosystem that is one of most critical issues for our sustainable life in the next era. There is a wide range of hydraulic engineering disciplines that are closely related multi-phase flows found in issues from disaster mitigation to preservation of nature. In this article, hydraulic engineering researches in the last decades are briefly overviewed focusing on multi-phase flows in a river system.
37 研究論文(国際会議プロシーディングス)
共著
Strategy for ecohydraulic management of vegetated river channel
Y. Ohchi, K. Aga H., Miyamoto and K. Kanda
E-Book: 9th International Symposium on Ecohydraulics 2012 Proceedings

4pages
2012/09
978-3-200-02862-3


Vegetation overgrowth on flood plains is a world-wide engineering issue in many rivers. This brings not only degradation of flow conveyance capacity but also irreversible changes in the ecological system of rivers. In
order to obtain information on tree vegetation behaviors during flood events, a field measurement of flow fields and tree vegetation was conducted in Kako River, where willows and bamboos, which are the predominant species, heavily vegetate the flood plain. Several flood events were observed after starting the H-ADCP flow measurement in 2009. The observed flow structures in and around the tree vegetation were successfully reproduced by a two-layer hydraulic model which was able to describe tree destruction area after the floods. The model can evaluate the drag force momentum for given conditions of discharge, river morphology and vegetation structure. Discussion was made with respect for a strategy for river and vegetation management by performing a parametric analysis of flows in vegetated channels under assumed conditions of forest thinning and floodplain excavation.
38 (MISC)総説・解説(学術雑誌)
共著
ダム技術の継承について
角哲也,小浪尊宏・川崎将生
河川

2012/ 8月, 20-24
2012/08



ダム技術の継承と技術者の育成に対する各国の取り組みをICOLDのオーガナイズドセッションで構成し,その学術交流成果をセッション・チェアマンとして報告した.
39 (MISC)総説・解説(学術雑誌)
単著
Knowledge & Technology Transfer in Dam Engineering,ICOLD2012,国際シンポジウム,セッション3報告

大ダム

220, 83-85
2012/07
0011-5347


本セッションでは, 8ヵ国(イギリス,オーストラリア,日本,ルーマニア,インドネシア,イラン,スイス,エジプト)から11編の論文が発表された.ポスターセッションには3件の関連研究も参加している. 11編の内訳は,ダム技術の継承問題が9編ダム技術の歴史的総括が1編,洪水管理の研究・技術ネットワークが1編,そして若手技術者や市民へのダム技術の広報・啓発が1編であった.ダム技術の継承に関しては,各国が直面する共通の課題が浮き彫りになり,シンポジウムの副題が象徴するように,次世代と世界各地へのダム技術の継承-伝達の重要性が再認識された.
40 研究論文(国際会議プロシーディングス)
共著
An in-situ experiment on oxygen solubility of mcro-bubble aeration in a eutrophic dam-reservoir
H. Minagawa, S. Yamada, T. Ikeguchi and N. Ohkawa
Intnl. Sympo. Dams for a Changing World, ICOLD 2012

2-99-2-104
2012/06



In a dam-reservoir with long hydraulic retention time, density field tends to be thermally stratified and the hypolimnion becomes anoxic due to eutrophication. In such anoxic water, nutrients, ionic metals, dissolved organic matters, etc. are significantly released and high amount of hydrogen sulfide and methane are also generated from sediments by biochemical reduction. In order to minimize such environmental hazards, oxygen needs to be artificially supplied into the hypolimnion with some aeration equipments.
Micro bubble aeration is one of promising techniques to efficiently feed oxygen to the anoxic water. In this study an in-situ experiment on micro-bubble aeration was carried out in a eutrophic reservoir by using two types of aerator. The experiment was started early summer when the hypolimnion was completely anoxic and the reservoir was thermally stratified with a sharp thermocline. The aeration system was intermittently operated by monitoring dissolved oxygen so that DO concentration was kept in a suitable range of concentration. The aeration was continued until the reservoir being uniformly mixed by fall overturn. A field measurement of temperature, dissolved oxygen and water quality was performed during the experiment. Performance of the two types of aeration systems was examined by evaluating oxygen capacity transfer oefficients.
41 (MISC)総説・解説(学術雑誌)
単著
総合治水への期待と実質化に向けた課題

土木学会誌

97/ 4, 124
2012/04



昭和50年代から都市河川流域を中心に取り組まれてきた総合治水対策-今日では,地域社会や地球環境の変化を背景として,流域治水の枠組みを越えて,ハードからソフト施策に至るまで多様化した主体が取り組む治水の総称へと変質している.総合治水を実現する上での課題について論じた.
42 研究論文(学術雑誌)
単著
土木技術界を取り巻く社会情勢と今後の教育・人材育成について

土木学会論文集H(教育)

68/ 1, 1-1-
2012/02

10.2208/jscejeep.68.1

地域から全球に及ぶ規模で社会と自然が変容を続け,土木体系とこれを支える技術教育・人材育成に大幅な変革・改質が求められている.技術界を取り巻く国内外の情勢を分析し,持続的な人材育成と技術革新を果たすための課題を整理する.先進国を中心に進む社会経済活動の縮退,気候変動にともなう自然災害の巨大化・激甚化,技術者人材の経年的減少,アジア諸国の台頭を背景に渇望される日本の国際戦略,高等教育の質保証運動と技術者の資質向上,工事・業務の量的減少と質的拡散,プロジェクト主体の多様化,技術基準の国際化など,情勢変化の嵐が土木技術界を襲っている.史実に学ぶまでもなく,人類と文明を支える基盤はインフラの整備・管理である.土木技術の根幹をなす人材を確保するために必要な教育・人材育成の戦略転換を考える.
43 研究論文(学術雑誌)
共著
炭素・リン・微生物環境ならびに窒素負荷が浸出水の脱窒効率に及ぼす影響
田中健治・中道民広・八木正博・和田有朗
土木学会論文集B1(水工学)

68/ 4, I_619-624
2012/02

10.2208/jscejhe.68.I_619

A laboratory experiment on denitrification was carried out in order to develop a technology for treatment of leachate from municipal waste landfill. The authors have already collected fundamental data from a previous experiment on denitrification in a confined test tank. The present experiment was performed in a circulating test tank with inflow load. It was investigated how parameters such as carbon, phosphorus, denitrification bacteria and inflow nitrogen load influenced on denitrification rate. It was
found that phosphorus is an important control factor in addition to carbon in leachate denitrification. A negative functional dependency of denitrification rate on inflow load was also confirmed, which provides useful information for development and planning of a treatment plant capacity. A design concept for the leachate treatment was proposed based on the experiment.
44 研究論文(学術雑誌)
共著
河道の経年変化から見た樹林化の要因分析と持続的な河川管理のための方策
阿河一穂・神田佳一・魚谷拓矢
土木学会論文集B1(水工学)

68/ 4, I_745-750
2012/02

10.2208/jscejhe.68.I_745

Forestation on floodplain is now a world-wide issue from a river engineering viewpoint. Based on a field data analysis of river morphology, discharge and land cover in the last decades, a main cause of floodplain forestation was found to be decreased frequency of floodplain inundation after sequent channel restoration works. In order to perform an adaptive river management, a uniform flow analysis of vegetated channel is carried out for several cross sections from middle to downstream. It is investigated how floodplain excavation and thinning of tree vegetation modify flow structure and tree destruction during flood events. It is discussed based on the analysis what is a proper management strategy in order to create a safe and attractive river environment.
45 (MISC)総説・解説(学術雑誌)
単著
神戸大学市民工学科のチャレンジと発信

国づくりと研修

129, 20-21
2012/01



技術者教育に新たな取り組みが求められる現代社会を背景として地方大学が取り組んだ学科改変の一つの事例を紹介し,その功罪を総括した.
46 (MISC)会議報告等
共著
持続可能社会における国土・地域の再生戦略
嘉門雅史他
日本学術会議提言

39 pages
2011/09



経済の成長・拡大を基調とする往年の政策は、大都市圏の肥大化、地方都市・農山漁村の疲弊、自然環境の劣化をもたらした。成熟社会の今に至ってもなお払拭されない拡大期の理念や社会システムをこの時期に抜本的に改め、社会の縮減を前提とする国土・地域の経営戦略へと転じない限り、持続可能社会は達成されない。中長期的な視点と広域的ガバナンスの原理に基づいて、国土軸再構成のための4つの具体方策を提言した。
47 (MISC)速報,短報,研究ノート等(大学,研究機関紀要)
単著
多自然川づくりのための水工学研究

神戸大学環境報告書

2011, 15
2011/09



自然材料を用いた河川構造物の環境水理学的特性を明らかにし,多自然川づくりに供する知見を得るために実施された解析的・実証的研究を紹介する.
48 (MISC)総説・解説(学術雑誌)
単著
理数科離れに対する土木分野からの視点

土木学会誌

96/ 8, 92
2011/08



人心は益々インフラ技術から乖離し,公共事業をあたかも諸悪の根源であるかのごとく批判し,土木技術を支援する世論は希薄となっている.国内の教育が歪み,科学技術が軽視されることに起因して今日,理科教育と技術者教育は危機に瀕している.今一度,技術立国の原点に返り,人材育成を立て直す必要がある.
49 研究論文(国際会議プロシーディングス)
単著
Double-diffusive stratification composed of temperature and pollutant salinity in anoxic reservoir hypolimnion

Proc. 7th International Symposium on Stratified Flows

CD-ROM
2011/08
978-88-95814-49-0


Double-diffusion was observed in a eutrophic reservoir, where a stable salty layer associated with unstable temperature gradient was formed in the hypolimnion. The heat and salt were supplied by an inclined plume that was generated on an anoxic benthic layer through biochemical reduction of the water-sediment interface. Observed temperature and salinity showed well-defined step-like layer structures. Turner angle, Tu, was analyzed and found to be /2< Tu < -/4 and it was concluded that the "over-stable-type" thermosolutal convection was the formation mechanism of the observed characteristic density structures. Thickness of the convective layer typically ranged between 1-3m, which was theoretically estimated by considering heat-salt conservations and a marginal instability for the double-density structure
50 (MISC)総説・解説(その他)
単著
持続可能社会における土木教育に向けて

西日本高校土木教育研究会「創設50周年記念誌」


2011/07



中堅技術者の教育を担う工業高校の研究会において持続可能社会を支える教育を論じるために,話題提供と意見交換を行った.
51 (MISC)会議報告等
共著
気候変動下における水・土砂災害適応策の深化に向けて
小松利光他
日本学術会議提言

31 pages
2011/07



地球規模の気候変化と尖鋭化する水・土砂災害-これに対峙し,持続可能社会を形成するための政策戦略に対する学術的提言を発信した.
52 研究論文(国際会議プロシーディングス)
共著
Optimization of Reservoir Aeration with Consideration of Thermocline's Capping Effect
Y.Kobayashi, C.Aoki
Proc. Water 2010 Symposium

CD-ROM, 8 pages
2011/07



As a countermeasure against eutrophication, micro-bubble aeration was carried out to feed oxygen to anoxic hypolimnion in a reservoir. The aerator was intermittently operated so that oxygen concentration was kept at a desirable level between 5 to 10mg/l in the hypolimnion. Although a bubble was very fine and its lifting velocity was quite small, a part of them were lost from the hypolimnion due to their weak buoyancy. In the present study, it was investigated from oxygen balance analysis how much oxygen was lost from hypolimnetic depending on thermocline’s stability. It was found that less oxygen was lost with sharpening the thermocline due to its capping effect. The field data inidicates that the aeration facility can be most efficiently operated by varying aeration discharge depending on the season-dependent thermal structure. The knowledge obtained from the study could be useful in development of an optimum operation strategy of aeration systems.
53 研究論文(国際会議プロシーディングス)
共著
H-ADCP Flood Routing and Flow Modeling for Evaluation of Flow Conveyance Capacity in a Tree-Vegetated River Channel
H. Miyamoto, K. Kanda, Y. Ohchi, K. Aga, J. Morioka, T. Uotani, K. Yoshida, S. Yoshimura
Proc. 34th IAHR Congress

CD-ROM, 2878-2885
2011/07
978-0-85825-868-6


Although extensive research works have been performed on hydrodynamics of vegetated channels, little attention was paid on flow resistance mechanisms being dependent on submerged level of tree vegetation. The authors developed a 2-D two-layer model that can simulate flows not only through but also over the vegetation, which enables us to analyze all ranges of water level and vegetation height. A H-ADCP system was equipped in a river to measure a time-dependent velocity profile in span-wise direction. The H-ADCP data and information on tree destruction were collected from several flood events during 2009-2010, which were compared with the analytical solutions. The numerical solution was in good agreement with the observed flow fields and the destructed tree areas, respectively. The findings are to contribute to devise a proper and feasible river management strategy.
54 (MISC)総説・解説(その他)
単著
土木技術者の教育と人材育成における課題と取り組みの現状

土木施工

4月, 88-91
2011/04



土木技術者を目指す人材が減少する中で,今度取り組むべき,アドミッション・ポリシー,カリキュラム・ポリシー,ディプロマ・ポリシーを論じた.
55 研究論文(学術雑誌)
共著
経年化した廃棄物埋立処分地からの浸出水の脱窒処理に関する基礎的検討
和田有朗・中道民広・八木正博・松本敏秀・釘宮晃一
土木学会論文集B1(水工学)

67/ 4, I_1489-I_1494
2011/02

10.2208/jscejhe.67.I_1489

A laboratory experiment on denitrification was carried out in order to reduce nitrogen load from municipal landfill leachate. Nitrogen was efficiently removed by feeding sludge of the leachate pond into the tanks, which could activate denitrification bacteria. Although inorganic reducing agent such as iron powder was not able to make the whole water mass anoxic, denitrification took place by supplying organic matters such as methanol, hydrogen feeding agent, etc.. It is considered that small amount of anoxic water film produced on surfaces of container and carriers might contribute to denitrification, although the bulk water is kept aerobic. It is found that organic matters contained in the leachate is so insufficient that nitrification liquid circulation does not work well for denitrification.
56 研究論文(学術雑誌)
共著
樹林が繁茂した加古川中流部における出水時流況と樹林損壊に関する調査・解析
宮本仁志・神田佳一・大地洋平・阿河一穂・盛岡淳二・魚谷拓矢・吉田一亮・吉村敏
土木学会論文集B1(水工学)

67/ 4, I-1087-1092
2011/02

10.2208/jscejhe.67.I_1087

Forestation on flood plains is a world-wide engineering issue in middle to downstream reaches in many rivers. This brings not only degradation of flow conveyance capacity but also irreversible changes of ecological system in rivers. In order to obtain information on tree vegetation behavior during flood events, field data of flow fields and tree vegetation collapse were collected in Kako River, where willows are heavily vegetated on the flood plain. After starting a H-ADCP flow measurement in 2009, small to medium size flood events frequently occurred, which enables us not only to verify an analytical model to reproduce flow fields in and out of vegetations but also to examine tree vegetation collapses after flooding. The analytical solutions on velocity profiles as well as flow force acting on trees were in good agreement with the H-ADCP measurements and tree damages, respectively.
57 (MISC)その他記事
単著
科学の新領域と混相流-ビッグプロジェクト・国際プロジェクト-

混相流

24/ 2, 131
2010/06



特集趣旨
58 研究論文(学術雑誌)
共著
樹林化した河道の流況観測と樹林内外の流況・樹木抗力の解析
宮本仁志・神田佳一・大地洋平・阿賀一穂・盛岡淳二・魚谷拓矢・吉田一亮・吉村敏
河川技術論文集

16, 437-442
2010/06



Vegetation overgrowth in river channels has become a serious engineering problem for river management in Japan. It is not a feasible solution to cut off all the trees on flood plains in the channel maintenance program for river flood protection, ecological conservation, and economic administration. In order to manage the river channels in a lower cost system, it is necessary to make a suitable channel design in which vegetation on flood plains could be flushed out by natural flood flows with certain frequency. As an engineering tool for designing the suitable channel, a two-layer river flow model was developed in this paper, which could simulate the flows in both main channels and flood plains with tree vegetation. A significant feature of the present model is the capability of estimating the bed shear stress and the drag force acting on the vegetation. Field measurements of flood flows and vegetation structures confirmed the model capability. The analysis was in good agreement with the observation both on the flood flow fields and the damaged areas of vegetation in August 2009 flood event in the Kako River. It is expected that the findings from the study would contribute to construction of river management strategy.
59 研究論文(国際会議プロシーディングス)
共著
A water quality model for aeration of leachate from garbage dumped landfill
T. Nakamichi, M. Yagi, N. Wada
Proc. 6th Int. Symp. Environmental Hydraulics

2, 1053-1058
2010/06
978-0-415-58475-3


Landfill leachate from municipal solid waste brings serious contamination in downstream waters. Micro-bubble aeration is experimentally conducted in a laboratory tank and nitri-fication performance is investigated for the purpose of developing an economical water treatment system. Three types of gases, (i) natural air, (ii) oxygen and (iii) ozone, are used for the aeration. A water quality model is developed in order to reproduce water quality behaviors, where balances are considered in respect to dissolved oxygen, bacteria, ammonia, nitrite, nitrate and manganese. Simulated time-dependency of each water quality component is compared with the laboratory data and the model is in good agree-ment with experiment. The oxygen aeration tank showed most efficient nitrification among the three gasses.
60 (MISC)会議報告等
共著
これからの社会を担う土木技術者に向けて
近藤徹他
土木学会会長重点活動特別委員会報告書

84 pages
2010/05




61 (MISC)その他記事
単著
科学の新領域と混相流-次世代技術における混相流-

混相流

24/ 1, 12
2010/03



特集趣旨
62 研究論文(学術雑誌)
共著
酸素マイクロバブルを用いた貯水池深層曝気実験における水質改善効果の検討
南川久人・山田哲史・安田孝宏
日本実験力学会誌

10/ 1, 39-44
2010/03



An experimental study on the effects of water quality improvement using oxygenic micro bubbles aeration to deep layer in a reservoir was carried out for two systems using a micro bubble ejector. The first system sets the ejector near the benthic region of the reservoir, while the second one pumps water from the benthic region, inject micro bubbles near the water surface, and sends micro bubbles with water slowly in a larger pipe to the benthic region. As a result, improvement of dissolved oxygen concentration was recognized for both systems for the region between the injection level and the thermocline without the destruction of it. Moreover, from the view points of the electric conductivity and the oxidation reduction potential, water quality improvement was also confirmed. By comparison of the two systems, the second one got the better result for the improvement of dissolved oxygen concentration.
63 研究論文(学術雑誌)
共著
流出抑制及び面源負荷軽減対策としての雨水貯留施設による都市流域管理の研究
和田有朗・岸本宏司
水工学論文集

54, 1327-1332
2010/02



Since nonpoint pollutant sources in an urban catchment have a significant environmental impact on the quality in receiving waters, it is important to minimize pollutant loads from nonpoint source in the catchment. In this study, stochastic properties of rainfall events are analyzed by using precipitation dataset collected by the Kobe Marine Observatory during the past 40 years (1966-2005). A pollutant load runoff analysis was performed by using the Storm Water Management Model, SWMM, with consideration of pollutant load control by a stormwater storage facility. An investigating effect of storage facility capacity on water treatment performance , it was found that the storage tank functions in reducing peak flows discharge as well as minimizing non-point source pollutant loads. An optimal design for the storage tank was made in a test basin based on consideration of the analytical findings.
64 (MISC)総説・解説(学術雑誌)
単著
閉鎖性陸水域における環境負荷軽減のためのマイクロバブル技術

日本海水学会誌

64/ 1, 24-30
2010/01



河川流域に展開される社会経済活動は栄養塩・有機物などの汚濁負荷を与え水利用と自然環境に様々な障害をもたらす湖沼・貯水池などの閉鎖性陸水域においては流れが緩慢で自然浄化機能は小さく,流域から供給される物質負荷が時間累積値として水質に反映される.水中の溶存酸素は有機物,アンモニア性窒素,金属イオンなどによって消費されるとともに水が停滞して酸素供給が少ないため有機汚濁・水質障害が発生しやすい.水質改善のための有効な手段の一つは嫌気化した水域を好気的環境に復元することであり,高い酸素溶解効率を有するマイクロバブル曝気の利用が考えられる.本文ではダム貯水池など閉鎖陸水域の環境負荷軽減を目的としたマイクロバフール技術の適用例を報告する.
65 (MISC)その他記事
単著
教育・人材育成に求められるパラダイムシフト

CE建設業界

58/ 11, 47
2009/11




66 (MISC)その他記事
単著
情報化技術と混相流-安心・安全のための技術Ⅱ-

混相流

23/ 4, 381
2009/11



特集趣旨
67 (MISC)その他記事
単著
自然共生型流域圏の構築を目指した水圏環境工学の教育

神戸大学環境報告書

2009, 10-11
2009/09




68 (MISC)その他記事
単著
情報化技術と混相流-安心・安全のための技術Ⅰ-

混相流

23/ 3, 259
2009/09



特集趣旨
69 (MISC)その他記事
共著
日常生活を支え続ける24時間の土木,特集:土木の仕事
宮田喜寿他
国づくりと研修

125, 6-11
2009/08




70 研究論文(国際会議プロシーディングス)
単著
Micro-Bubble Aeration of Polluted Leachate from a Landfill

Proc. 33rd IAHR Congress

CD-ROM, 8 pages
2009/08



Leachate from garbage-dumped landfill brings serious contamination in downstream waters. Micro-bubble aeration was conducted in order to experimentally examine its purification performance. Three types of gases, (i) natural air, (ii) oxygen and (iii) ozone, were used for the aeration. Performance of water purification was discussed based on water quality measurements in the water tank experiments. The laboratory data showed that the most significant oxidation occurred in the oxygen aeration tank in which nitrification was accelerated most efficiently among the three gasses. Both the ozone and the atmospheric-air tanks show lower water purification performance. Manganese was most tremendously reduced through oxidation of ionic manganese by the oxygen aeration as well.
71 (MISC)その他記事
単著
自然共生型流域圏の構築による社会資本の再整備

建設の施工企画

6月, 7
2009/06



巻頭言
72 (MISC)その他記事
単著
情報化技術と混相流-混相流のビジュアル化-

混相流

23/ 2, 143
2009/06



特集趣旨
73 研究論文(学術雑誌)
共著
Numerical calculation of flows by a rubble mound groin by a combined model of a porous flow model with a non-Darcian resistance law and a 3-dimensional LES model
R.Akahori
J.Hydroscience and Hydraulic Engineering

27/ 1, 89-103
2009/05



This study presents a combined numerical model of a porous flow model that employs the non-Darcian resistance law and a 3-dimensional Large Eddy Simulation model in order to investigate three-dimensional and temporal structures of flows around a rubble mound groin. The model’s accuracy is cross-checked by comparing numerical results to observed results of an existing experiment, and the model's results show good agreement in terms of time- and depth-averaged sense. Calculation results also imply that a permeable groin restricts growth of secondary flows in a constriction section. However, a combined model is not able to produce unsteady characteristics of flows that are caused by small scale and structured turbulences in a down-stream region of a groin.
74 (MISC)会議報告等
単著
“RIVER FLOW 2008” The 4th International Conference on Fluvial Hydraulics参加報告

混相流

23/ 1, 97-98
2009/03




75 (MISC)その他記事
単著
情報化技術と混相流-混相流とセンサー技術-

混相流

23/ 1, 20
2009/03



特集趣旨
76 研究論文(学術雑誌)
共著
廃棄物堆積層からの浸出水の曝気・硝化過程に関する水質モデル
松本敏秀・和田有朗・山田怜奈
水工学論文集

53, 1333-1338
2009/02



Leachate from garbage-dumped landfill brings serious contamination in downstream waters. Micro-bubble aeration is experimentally conducted in a laboratory tank for the purpose of developing a new water treatment system. Water purification performance especially focusing on nitrification is investigated. Three types of gases, (i) natural air, (ii) oxygen and (iii) ozone, are used for the aeration. A water quality analysis is carried out in order to predict water quality behaviors, where balances are considered in respect to dissolved oxygen, bacteria, ammonia, nitrite, nitrate and manganese. Time-development of each water quality component is reproduced with satisfactory agreement and the model is verified through comparison with laboratory data. The data show that the oxygen aeration tank showed most efficient nitrification among the three gasses.
77 (MISC)その他記事
単著
地球環境と混相流-サスティナビリティと地域・社会環境Ⅱ-

混相流

22/ 4, 321
2008/12



特集趣旨
78 研究論文(国際会議プロシーディングス)
共著
A two-layer model for analyzing flow field, bed shear stress and drag force in a tree-covered river channel
N.Morioka, H.Miyamoto, R.Akahori
Proc. 2nd International Symposium on Shallow Flows

CD-ROM, 6 pages
2008/12



A two-dimensional numerical model is developed in order to analyze flow field in a river channel that is par-tially covered by tree vegetations. The flow system is two-layered divided by an interface so that the two-layer interface encompasses vegetation canopies. The model is able to describe flows not only in the water phase but also in the bush. Two types of mechanism that collapse the tree vegetation are considered; the first one is drag force that bends down a tree and the second one is bed shear stress that scours the bed materials around a tree and pulls it up by the root. It was found through the analysis that the drag force becomes comparatively predominant and the bed shear stress becomes less important with increasing the vegetation density.
79 (MISC)その他記事
単著
地球環境と混相流-サスティナビリティと地域・社会環境Ⅰ-

混相流

22/ 3, 223
2008/09



特集趣旨
80 (MISC)総説・解説(学術雑誌)
単著
貯水池深層の酸化還元条件と水理学的・生物化学的熱塩諸現象

混相流

22/ 3, 249-256
2008/09



Heat and mass transport in eutrophic reservoirs are discussed with focusing on water quality behaviors that depends on oxygenation-reduction potential in hypolimnion. The author paid his attention on an inclined gravity current that is generated on a sloping benthic layer through hydraulic and biochemical processes. The gravity current is responsible for production of various characteristic heat-salt density fields such as inverse thermal stratification, diffusive-type double density structure, high concentration of pollutants in the bottom layer and meromictic density stratification throughout a year, which cause serious hypolimnetic contamination. Micro-bubble aeration was carried out in order to control the oxygenation-reduction condition, to modify heat-salt transport and eventually to purify the hypolimnion. The water purification was very successful and all the characteristic water quality structures completely disappeared. The heat-salt processes found in this study are new contamination mechanisms that have never been discussed in previous studies.
81 研究論文(国際会議プロシーディングス)
共著
Analysis on river flow in and around rubble mound groynes
Z.Li, K.Kanda
Proc. RIVER FLOWS 2008

1, 843-850
2008/09



Since a rubble mound groyne has a permeable structure, through-flow water can be purified, pores and concaves of the mound provide living space for aquatic lives, and landscape around the structure is nicer and more natural than those of artificial modern structures. In this study, focusing its attention on a set of rubble mound groynes, a field observation and a flow analysis were carried out in Akashi River in Hyogo, Japan, where some groynes were partially damaged by a flood flow in 2004. A two-dimensional flow model was developed in order to reproduce flow fields during the flood and to estimate flow force acting on the structure. Hydrodynamics inside and outside the rubble mound groyne was discussed. Characteristics of the flow such as streamline conversion and diversion around the structure, shear stress on the river bed and profiles of drag force acting on the structure were investigated.
82 研究論文(学術雑誌)
共著
雨水貯留施設の施設規模決定の費用対効果に関する研究
和田有朗・岸本宏司
河川技術論文集

14, 211-216
2008/06



Non-point sources in an urban rivers catchment have a siginificant environmental impact on the quality in the the public recieiving waters. Therefore, it is important to minimize the non-point source pollutant loads from the catchment. In this study, we analyzed rainfall dataset during the past 20 years (1985-2004) collected by the Kobe Marine Observatory, and determined stochastic characteristics of rainfall that are closely related to heavy pollutant loads. We performed a pollution load simulation analysis by using a storm water runoff storage tank, to determine the optimal capacity for the tanks, in terms of the cost-benifit analysis considering the removal rate of the pollution load and construction costs. It was found that the stormwater storage tank is efficient not only for controlling runoff discharge but also for minimizing pollutant loads.
83 研究論文(学術雑誌)
共著
非ダルシー型抵抗則を用いた捨石水制内部流れおよび3次元LESによる水制周辺流れの数値計算
赤堀良介
水工学論文集

52, 1045-1050
2008/02



This study present a combined numerical model of a porous flow model that employ a non-Darcian resistance law and a 3-dimensional Large Eddy Simulation model in order to investigate 3-dimensional and temporal structures of flows around a rubble mound groin. A model’s accuracy is cross-checked by comparing numerical results to observed results of an existing experiment, and model's results show good agreement in terms of time- and depth-averaged sense. Calculation results also imply that a permeable groin restricts growth of secondary flows in a constriction section. However, a combined model is not able to produce unsteady characteristics of flows that are caused by small scale and structured turbulences in a down-stream region of a groin.
84 研究論文(学術雑誌)
共著
成層安定度を考慮した深層曝気の必要送気量の推算
小林憂三・青木千夏・原義晴・松尾克美
水工学論文集

52, 1279-1284
2008/02



In order to properly determine oxygen discharge of a micro-bubble aeration system, dissolved oxygen and relating water qualities were measured in an anoxic reservoir hypolimnion. Consumption and loss amounts of the oxygen were estimated by analyzing oxygen balance. It was found that the oxygen loss rate linearly decreases with increasing dynamic stability of thermal stratification. A seasonal dependency of oxygen consumption due to biochemical activities was also obtained from the field dataset. Aeration discharge necessary for keeping the hypolimnion aerobic was estimated by summarizing the analytical results, which provides necessary information for optimizing the system operation. The proposed method for estimation of aeration discharge was expected to minimize both the energy consumption and the system capacity.
85 研究論文(学術雑誌)
共著
廃棄物堆積層からの浸出水の浄化処理に関する実証試験
山田怜奈・松本敏秀・釘宮晃一・中道民広・伊藤義明・八木正博・原義晴
水工学論文集

52, 1273-1278
2008/02



In order to optimize treatment of leachate from garbage-dumped landfill, a micro-bubble generation technique was applied to feed oxygen into an anoxic layer of the leachate reservoir. Although the impounded water was successfully aerated and dissolved oxygen recovered a great deal, nitrification of ammonia did not so extensively occurred. The limiting factor of nitrification was found to be biochemical reaction that were not activated so much due to insufficient amount of bacteria colonies under relatively low water temperature. Most of the oxygen demand in the leachate was caused by ammonia but not by organic compounds, which was a very different water quality feature from that in rivers and lakes. Additional finding was that chemical oxygen demand of the leachate was highly correlated with ammonia concentration as well as with electric conductivity.
86 (MISC)総説・解説(学術雑誌)
単著
ダム貯水池の貧酸素化にともなう諸問題と水質管理

ダム技術

254/ 11, 3-8
2007/11



ダム貯水池の有機汚濁は植物プランクトン(浮遊藻類)が栄養塩を吸収し増殖することによって進行する。河川で植物プランクトンがほとんど発生しないのは,河川流の乱れによって細胞がストレスを受け生存できないためである。したがって理屈上では,曝気循環などにより貯水池全層を乱流状態に維持すれば藻類の増殖を抑制することは可能であるが,そのように大規模な運転は事実上不可能である。現実的には水質障害を最小化するための局所的な技術対策が様々に実施されている。本稿では富栄養化による貧酸素現象とそれに付随する水質問題に着目して,これまで認識されていなかったいくつかの水質水理現象を紹介して問題を提起し,今後の水質管理のあり方を考える。
87 研究論文(学術雑誌)
共著
An Experimental Study on Flow Field in and around Rubble Mound Structures
K.Takehara, T.Etoh
J.Hydroscience and Hydraulic Engineering

25/ 2, 37-45
2007/11



In order to understand more clearly hydrodynamics of rubble mound weirs and groins as environmentally-friendly river structures, the flow fields around them were experimentally investigated. In a physical model experiment, the flow inside the structure was visualized by adjusting the refraction indexes between the working fluid and the materials of the rubble. Velocity vectors were obtained by means of PIV. It was found that mass and momentum exchange between the main flow and the rubble’s porous media was predominant around the upstream and downstream corners of the weir and the groin, where streamline was rapidly contracted. Therefore, turbulence energy was significantly produced there, which eventually caused a high intensity of turbulence. The turbulent structure in the rubble mound was almost independent of ambient flow fields, and was also primarily influenced by the rubble-pore arrangement.
88 研究論文(学術雑誌)
共著
Mechanism of Deoxygenation in Reservoir Metalimnion
H.Kotani, S.Sasaki, Y.Nishiguchi
J.Hydroscience and Hydraulic Engineering

25/ 2, 23-35
2007/11



It was found in a eutrophic reservoir that the metalimnion became anoxic during the hot season while the hypolimnion became sufficiently aerated. The cause of metalimnion deoxygenation was investigated by means of field measurements. The field data suggests that dissolved oxygen in the metalimnion was more significantly consumed in the sidearm than in the main reservoir. The two mechanisms that may accelerate deoxygenation in the sidearm are discussed. The first one is the production and settling of organic matter in the sidearm, where greater algae blooming occurred than in the main reservoir, eventually leading to the long-term suspension of organic solids and the resultant oxygen consumption in the hypolimnion. Little oxygen is supplied there because the stable density stratification prevents the aerated hypolimnetic water from rising up. The second mechanism is the sediment oxygen demand that was most significant at a point where the metalimnetic water intersects the reservoir bed. Large amounts of nutrients, metals and other components were reduced from the sediment under such anaerobic conditions which increased the local water density and generated a horizontal intrusion of the anoxic hypolimnetic water into the main reservoir. At the same time this density current transported pollutants from the sidearm to the main reservoir.
89 (MISC)総説・解説(その他)
単著
捨石河川構造物の水理特性

水工学シリーズ

07/ A-4, A-4-1-17
2007/08



石礫や木材など自然素材を用いて河川流を柔に制御する河川構造物は古来より多様されており,近年の多自然川づくりにおいても高い環境再生機能と流水制御機能を持つ工法として認められている.しかし,伝統工法であるが故にその機能が水理学的に評価されているわけではなく,合理的な構造設計ができない現状にある.本研究では,石礫を用いた水制,井堰,護岸などの構造物を対象に二次元二層流モデルで流体力や流れ場,さらに流量制御機能を評価し,石礫構造物の機能を水理学的に評価する手法を提案している.
90 研究論文(国際会議プロシーディングス)
共著
Hydraulic Characteristics of A Group of Permeable Groins Constructed in An Open Channel Flow
Z.Li, S.Maeno
Proc. 32nd IAHR Congress

CD-ROM, 11 pages
2007/07



In this study, a numerical analysis and a laboratory experiment were carried out in respect to an open channel flow with a group of permeable groins installed. By using a two-dimensional depth-averaged numerical model, flow fields and water surface profiles were analyzed and compared with the laboratory data. The model was developed by taking consideration of flow resistance and permeability of the rubble mound structures, which is expected to be a useful tool for making hydraulic design of permeable river structures such as rubble mound groins. The agreement between the analysis and experiment was satisfactory. Effects of rubbles' porosity and diameter and arrangement of the groins on the flow structure and fluid forces were discussed based on the experimental and the numerical data.
91 研究論文(学術雑誌)
共著
自然環境と河川環境の評価に関する研究
和田安彦・和田有朗
土木学会論文集G

63/ 3, 168-178
2007/07



本研究では,自然的要素や河川の利用状況と河川環境の異なる都市河川を対象に,住民が抱く河川に対するイメージや要望,河川で行いたいリクリエーション活動などの河川環境に対する意識を明らかにした.その結果,住民が抱く河川に対するイメージや要望については,河川環境が異なっても意識が類似していることが明らかとなった.また,住民意識の違いによる河川に対する価値評価をCVMを用いて行った結果,現況の河川に対する満足度が高く,河川環境の保全・美化活動に対する参加意識が強いほど,河川に対する価値評価が高いことを明らかにした.
92 (MISC)総説・解説(学術雑誌)
単著
マイクロバブルによる貯水池深水層などの水質浄化

クリーンテクノロジー

17/ 6, 49-53
2007/06



流域に展開される多様な人間活動は栄養塩・有機物などの汚濁負荷を生産し,廃棄物を生み出す.その結果,河川から海域に至る水質は悪化し,水利用と自然環境に障害をもたらす.本文では,貯水池の深水層や一般廃棄物埋立処分場から浸出する汚濁水を対象として,マイクロバブルを利用した水質浄化技術の事例を報告する.
93 研究論文(学術雑誌)
共著
透過水制が設置された河川流の解析
李最森・神田佳一・前野詩朗
河川技術論文集

13, 237-242
2007/06



Since a rubble mound groin has a permeable structure, through-flow water can be purified, pores and concaves of the mound provide living space for aquatic lives, and landscape around the structure is nicer and natural than those of artificial modern structures. In this study, focusing our attention on a set of rubble mound groins, a field observation and a numerical analysis were carried out in Akashi River in Hyogo, Japan, where the groins was partially damaged by a flood flow in 2004. A two-dimensional flow model was developed in order to reproduce flow fields during the flood and to estimate flow force acting on the structure. Hydrodynamics inside and outside the structure was discussed based on the numerical analysis. Characteristics of the flow such as streamline concentration and diversion around the structure, shear stress on the river bed and profiles of drag force acting on the structure were investigated.
94 研究論文(国際会議プロシーディングス)
単著
Strategy of Water Purification in Dam Reservoirs

Proc. 4th Civil Engineers Conference in the Asian Region

CD-ROM, 4 pages
2007/06



Focusing on water purification of reservoirs, engineering countermeasures against deoxygenation in hypolimnion and metalimnion will be discussed. The first topic is on a new aeration system which is to purify the hypolimnetic water by feeding micro-bubbles. The aerations were successfully done in two reservoirs by using natural air and oxygen, respectively. The second topic is deoxygenation of metalimnion and strategy of engineering countermeasure against this. The adequate capacity necessary for minimizing the anoxic metalimnetic water was analyzed based on the water quality simulation and cost performance evaluation.
95 (MISC)総説・解説(学術雑誌)
単著
Nutrient-sediment loads from forest catchment and its influence on lake and reservoir eutrophication

水工学論文集

51, K3-K6
2007/02



Land-cover types in watersheds have a significant impact on water quantity and quality as well as on ecological cycles in lakes and reservoirs. Dependencies of substance loads from forest catchments on land-cover are discussed with a particular focus on nutrients and sediment. Ecological processes and the eutrophication mechanism in lakes and reservoirs are briefly reviewed. The relationship between water quality in lakes and reservoirs and the nutrient production from forest catchments is discussed. Algae bloom and the resultant eutrophication are predominantly controlled by a phosphorus load that is highly correlated with the sediment load. As forest-cover decreases in the catchment, the sediment and nutrient loads increase and eventually promote eutrophication in lakes and reservoirs. Since field data indicate that the clearing and collapse of forests result in a significant increase in the runoff rate and nutrient load, proper management of forests is one of the key issues for protecting the water environment.
96 研究論文(学術雑誌)
共著
降雨の確率特性を考慮した雨水貯留施設の汚濁負荷削減効果に関する検討
和田有朗・岸本宏司
水工学論文集

51, 1147-1152
2007/02



In this study, we performed a statistic analysis of rainfall events (the duration of dry days, the average rainfall intensity, the rainfall duration) using rainfall data for 20 years collected from the Kobe Marine Observatory, and also made a pollutant load run-off analysis using a Storm Water Management Model (SWMM). These data were used to examine stochastic characteristics of rainfall that are closely associated with pollution loads. The results of the analyses revealed that the Kobe area has frequent rainfall events with a combination of a rainfall intensity of 4 mm/hr and a rainfall duration of 25 hours. It was also found that the cumulative amount of pollution load runoff caused by a single round of rainfall was often about 5 to 10 kg in the river basins examined. We examined the effect of a storm water storage tank, in terms of reducing the pollution load, considering the stochastic characteristics of rainfall. It was found that a storage tank would be an effective measure for preventing inundation and also help to reduce the pollution load, through the effect of delaying rainfall run-off.
97 研究論文(学術雑誌)
共著
捨石透過水制を配した開水路における流れと河床変動
李最森・前野詩朗・和中隆志
水工学論文集

51, 817-822
2007/02



In this study, a numerical analysis and a laboratory experiment were carried out in respect to an open channel flow field with a movable bed in which a permeable groyne was installed. By comparing the agreement between the analysis and the experiment, the influence of the permeable groin to the open channel flow and movable bed erosion were discussed. The numerical method was expected to provide knowledge to the design of river structure such as permeable rubble mound groyne.
98 研究論文(学術雑誌)
共著
中層貧酸素化の軽減を目的とした貯水池曝気施設の計画
小谷英之・小林秀典
水工学論文集

51, 1355-1360
2007/02



It was found in a eutrophic reservoir that the metalimnion became anoxic during the hot season while the hypolimnion became successfully aerated. As countermeasures against deoxygenation of the reservoir metalimnion, performance of three types of aeration systems, i.e. (i) air diffuser system, (ii) air bubbler destratification system and (iii) air bubble jet system, was evaluated by making a numerical analysis of water quality. In the analysis, physical processes such as dissolved oxygen dilution and vertical mixing caused by aeration were taken into consideration in addition to hydrodynamics and biochemical processes regarding to water quality. The system’s performance was examined from view points not only of water purification but also of cost-benefit performance. It was found through the analysis that the air bubbler destratification system shows the best performance. System’s capacity necessary for the aeration was also discussed.
99 研究論文(学術雑誌)
共著
ゴミ埋立処分場からの浸出水のマイクロバブルによる水質浄化
釘宮晃一・山田怜奈・伊藤義明・八木正博・中道民広
水工学論文集

51, 1403-1408
2007/02



Leachate from garbage-dumped landfill brings serious contamination in downstream waters. A micro-bubble aeration was conducted in order to experimentally examine its purification performance. Three types of gases, (i) atmospheric air, (ii) oxygen and (iii) ozone, were used for the aeration. Performance of water purification was discussed based on water quality measurements in a water tank experiment. The experiments were carried out in summer and winter. The laboratory data showed that the most efficient oxidation occurred in the oxygen aeration tank in which nitrification was accelerated most significantly among the three gasses. Both the ozone and the atmospheric-air tanks show lower water purification performance. Manganese was tremendously reduced through oxidation of ionic manganese by the oxygen aeration as well.
100 研究論文(学術雑誌)
共著
鉛直2次元モデルによる多孔質堰を通過する流れの解析
前野詩朗・小川誠
土木学会論文集B

63/ 1, 16-28
2007/01



近年,環境面に優しい自然石礁で構築される多孔質水理構造物が注目 されている.本研究では,多孔質水理構造物の一つである多孔質堰周辺流れを精度良く再現できる解析モデを提案した.解析モデルでは周辺の複雑な自由表面を表現できるVOF法を適用した.また,基礎式中に多孔質抵抗として層流抵抗と乱流抵抗の両者を考慮した抵抗則を導入した.非越流状態と越流状態の流れを対象にして解析を行った結果,提案した解析モデルは多孔質堰周辺の流れを精度良く再現することが確認された.
101 研究論文(国際会議プロシーディングス)
共著
Thermosolutal Stratification and Water Quality Behaviors in a Reservoir Hypolimnion before and after Micro-Bubble Aeration
T.Kanda
Proc. 6th Intnl. Sympo. On Stratified Flows

775-780
2006/12



A field measurement was performed in a reservoir to investigate a special mechanism of hypolimnetic contamination. The authors focused their attention on an inclined plume generated on a sloping benthic layer whose driving force is the specific density difference between the salty water in the benthic layer and the ambient water. The salty water is produced through a bio-chemical reaction or reduction of bed materials that are exposed to anaerobic ambient water. It was found that the plume transports a significant amount of dissolved compounds such as metals, nutrients, organic and inorganic matter, etc. After a five years long measurement, hypolimnetic aeration started by using a micro-bubbled aeration. The hypolimnion was so successfully purified that both of the inverse temperature stratification and the highly concentrated dissolved substances completely disappeared. The result shows that the chemical inclined plume was no more produced after the hypolimnetic aeration
102 研究論文(学術雑誌)
共著
閉鎖性海域湾奥部における放流施設建設時の環境影響の評価
山下克己・有光剛
電力土木

326, 32-41
2006/11



周囲を埋立地で固まれた閉鎖性海域 湾奥部の雨水ポンプ場の建設に先立ちポンプ場からの放流による環境変化を水理模型実験及び、数値計算から評価した。水理模型実験により放水口前面の水位変動,流速及び底 泥の巻き上げ量を,数値計算により塩分及び濁度分布を評価した。その結果,周辺河川の影響が大きく,漁業への影響が懸念された塩分及び濁度はポンプ場建設前後で大きな変化は予想されなかった。船舶の航行に影響を及 ぼす水位変動は小さいが,放水口近傍での流速が大きく,放水口の形状検討を行い流速を低減した.
103 研究論文(学術雑誌)
共著
兵庫県上郡町・安室川における淡水山紅藻チスジノリ配偶体の出現-特に河川の流量変化との関係について-
佐藤祐司・横山正・真殿克磨・辻光浩・水野雅光・魚留卓・妹尾嘉之・杉野伸義・永野正之・三橋弘宗・浅見佳世・原田一二三
陸水学雑誌

67, 127-133
2006/10



兵庫県上郡町の安室川では,2004 年1 月の調査で9 年ぶりに淡水産紅藻チスジノリ(Thorea okadae)の配偶体の生育が確認された。安室川のチスジノリは水中の石やコンクリート壁に着生していた。チスジノリが多く出現した場所の水深は20 ~ 100 cm,流速(表層)は14 ~ 84 cm s-1 の範囲にあった。1991年から2004 年までの,チスジノリ配偶体の出現状況と河川流量変化との関係を解析した。その結果,日平均流量最大の洪水が夏期(7 ~ 8 月)に発生し,それ以降に大きな洪水がなかった場合に,その年の秋から翌年の春にかけて配偶体は多数出現する傾向にあることが示唆された。なお,下流側の調査地点(C区域)では,川床の石に着生するチスジノリの胞子体(Chantransia stage)も見出された。
104 (MISC)総説・解説(その他)
単著
深水層の酸素環境が貯水池の水質生態系と流れにおよぼす影響

第9回水源地生態研究セミナー講演集,ダム水源池環境整備センター

43-61
2006/09




105 研究論文(国際会議プロシーディングス)
共著
Reservoir purification by using micro-bubble aerator
Sakatani,Y., Matsuo, K., Oda, T. and Hara, Y.
Proceedings of the 7th International Conference on HydroScience and Engineering

1-10
2006/09
0977447405


A new hypolimnetic aeration system was devised and its performance of water purification was examined in in-situ experiments. The system feeds fine micro-bubbles to the anoxic hypolimnion. Two types of aeration were conducted; the first one was aeration with natural air and the second one was oxygen aeration. It was confirmed in both of the experiments that the hypolimnion was kept aerobic even during midsummer, while it used to be kept completely anoxic in the absence of aeration. Since the oxygen micro-bubbles show higher solubility than the air micro-bubbles, dissolved oxygen in the hypolimnion was greatly recovered and even over-saturated in the case of oxygen aeration. In both cases, the micro-bubble aeration scarcely agitated the water, thus causing the thermal stratification to be well-preserved without generating predominant vertical mixing. Although the reservoir had suffered from serious oxygen depletion and contamination in the hypolimnion before the aeration, concentrations of nutrients, manganese and iron significantly decreased after starting the hypolimnetic aeration. The two reservoirs are now almost free from hypolimnetic contamination.
106 研究論文(国際会議プロシーディングス)
単著
Chemical gravity current and exchange of oxygen, nutrients and metals across a sediment-water interface in an anoxic sloping benthic layer

Proc. 15th APD-IAHR

63-72
2006/08



A stratified flow is generated along an inclined bed when density anomaly is produced by the anaerobic release of dissolved substances, such as non-organic nutrients and metal ions, from a "water-sediment" interface. A hybrid analysis of turbulent transport in the overlying water and of chemical and biochemical reactions in the sediment was performed in order to obtain solutions for the release flux of phosphate and ferrous iron, sediment oxygen demand, the profiles of their concentration, and velocity. It was discussed how the bed slope, the amount and velocity of dissolved oxygen in the overlying water, and the concentration of phosphate and ferrous iron in the sediment affect the transport rate of dissolved substances and sediment oxygen demand. The present study shows that the buoyancy effect plays an important role in water quality transport across an anoxic "water-sediment" interface.
107 研究論文(国際会議プロシーディングス)
共著
Deoxygenation and contamination of reservoir metalimnion
Kotani, H.
Proc. 2nd Intl. Conf. Environmental Science and Technology

I, 73-79
2006/08



It was found in a eutrophic reservoir that the metalimnion became anoxic during the hot season while the hypolimnion became successfully aerated. The cause of the metalimnion deoxygenation was investigated through field measurements. The field data suggests that dissolved oxygen in the metalimnion was more significantly consumed in the sidearm than in the main reservoir. Two mechanisms that may accelerate deoxygenation in the sidearm are discussed. The first one is the production and settling of organic matter in the sidearm, where higher algae blooming occurred than in the main reservoir, eventually leading to the long-term suspension of organic solids and the resultant oxygen consumption in the hypolimnion. Little oxygen is supplied there, because the stable density stratification prevents the aerated hypolimnetic water from rising up. The second mechanism is the sediment oxygen demand that was most significant at a point where the metalimnetic water intersects the reservoir bed. Large amounts of nutrients, metals and other components were reduced from the sediment under such anaerobic conditions, increasing the local water density and generating a horizontal intrusion of the anoxic hypolimnetic water into the main reservoir. At the same time this density current transported pollutants from the sidearm to the main reservoir.
108 (MISC)その他記事
単著
Closure to "Discharge through a Permeable Rubble Mound Weir" by Kohji Michioku, Shiro Maeno, Takaaki Furusawa, and Masanori Haneda

J. Hydraulic Engineering, ASCE

32/ 4, 433-434
2006/04



Discussion
109 研究論文(学術雑誌)
共著
Comparative study on recreative functions of rivers in Hanshin Area
Wada,N.
J. Environmental Information Science

34/ 5, 21-30
2006/03



This paper deals with the outcome of improvement to waterfront facilities along rivers running through urban areas. It discusses the construction of and improvements to riverfront facilities, taking into account the results of water quality research along those rivers. The nature of waterfront land usage, as well as the water quality of several rivers running through urban areas, was investigated through field research. It was found that construction within and improvements to areas along urban rivers could be roughly divided into two aspects: linear utilization of land running along the riverside and the use of tracts of land adjacent to the river properties. It was found that when the waterfront is made more useful to the local populace, access to the river increases, resulting in enjoy healthful recreation on the part of the citizenry.
110 研究論文(大学,研究機関紀要)
単著
捨石護岸を有する開水路流の解析
李最森・熊田清敬
神戸大学大学院自然科学研究科紀要

24/ B, 25-30
2006/02




111 研究論文(学術雑誌)
共著
酸素マイクロバブルを用いた貯水池の水質浄化システム
酒谷祐輔・松尾克美・尾田敏範・原義晴
水工学論文集

50, 1357-1362
2006/02



n order to purify reservoir hypolimnion most efficiently, a new system was developed by using an oxygen micro-bubble aerator. Since the oxygen micro-bubbles show much higher solubility than the air micro-bubbles, dissolved oxygen in the hypolimnion was tremendously recovered and even over-saturated. In addition the micro-bubble oxygen scarcely agitated water and thus the thermal stratification was well preserved without generation of predominant vertical mixing. While the reservoir was suffered from serious deoxidation and contamination in the hypolimnion before the water purification, concentrations of nutrients, manganese and iron significantly decreased right after starting the hypolimnetic aeration. The hypolimnion is now almost free from contamination and the system successfully shows high performance of water purification.
112 研究論文(学術雑誌)
共著
都市河川の水質が親水機能におよぼす影響
和田有朗
環境情報科学論文集

19, 89-94
2005/12



In this research we investigated what advantages people who live near the water want to receive from their environment, and what sorts of improvements of the waterside they would like to see. To that end, we analyzed the images of the waterside environment held and the ideas about the need for improvement expressed, comparing city-dwellers who are satisfied with their waterside environment and those who are not satisfied. We also included age as a factor. The results of our analysis indicated that those who are dissatisfied find it difficult to gain any enjoyment of nature or come into contact with nature at the waterside near which they live, as compared with those who are satisfied. We also found that young people want to use the river area for sports and other physical exercise, while older people want to enjoy nature along the shore. These findings indicated that the waterside environment should be improved in various ways, including improving the quality of the water; constructing promenades that feature natural scenes and creating spaces where people can observe nature; and dividing the waterside into different zones according to use, i.e., for camping, water skiing or sports. It is also important to publicize progress in waterside improvements that are intended to make them attractive, because many citizens are not interested in their local rivers.
113 研究論文(学術雑誌)
共著
開水路に設置された透過型構造物内部の流れ・乱れの計測
竹原幸生・江藤剛治・高橋亮介・南條雅志
土木学会論文集

No.803/ II-73, 105-114
2005/11



捨石・木材・異形ブロックなどで構築された透過型構造物の環境機能を評価するためには,多孔体内部の流れや乱れが水質・生態系などにおよぼす影響を明らかにする必要がある.本研究では,屈折率整合技術を用いて透過型構造物の内部・周辺の流れを画像計測し,流れと乱れの構造特性を検討した.PIVにより粒径や間隙配置などの多孔体構造が流れ・乱れにおよぼす影響,「構造物間隙-周囲流体」間の質量・運動量交換特性などが明らかにされた.本研究で得られた知見は,流体力など構造設計に必要な情報であると同時に,透過型構造物による曝気促進や礫間浄化能力,生息空間としての間隙の役割など透過型構造物の自然環境機能を評価する上で有用である
114 研究論文(学術雑誌)
共著
捨石水制群の水理特性について
李最森・前野詩朗・牛田高裕・藤井淳
応用力学論文集

8, 773-782
2005/09



In this study, a numerical analysis and a laboratory experiment were carried out in respect to an open channel flow field with a group of permeable groins installed. By using a two-dimensional depth-averaged numerical model, flow fields and water surface profiles were analyzed and compared with the laboratory data. The model was developed by taking consideration of flow resistance and permeability of the rubble mound structures, which is expected to be a powerful tool for making hydraulic design of rubble mound groins as well as other permeable river structures. The agreement between the analysis and experiment was fairy satisfactory. Effects of rubbles' porosity and diameter and geometry of the group of groins on the flow structure and flow force were discussed based on the experimental and the numerical data.
115 研究論文(国際会議プロシーディングス)
共著
Two-dimensional analysis on solid-liquid-phase flow in and open channel with a rubble mound groin
Nanjo,M., Ishigaki,T. and Maeno,S.
Proc. 31st IAHR Congress

2870-2879
2005/09



A two-dimensional numerical model was developed for describing the solid-liquid-phase flow in an open channel where a permeable rubble mound groin was installed. The computational domain in the analysis was divided into two regions, i.e. (1) a single-phase open channel flow and (2) a liquid-solid-phase flow consisting of an upper layer over the rubble mound groin and a porous media flow inside the groin. The whole domain was considered to have a two-layer structure with an interfacial boundary at the same level as the rubble mound's top surface. Momentum and mass exchange through the interface was taken into account by using the concept of entrainment velocity between the upper and lower layers. Numerical solutions for flow velocity and water depth were obtained not only outside but also inside the groin. In addition, the drag force in the rubble mound and the internal shear stress acting on the groin's top surface can be computed by the model. The analysis was verified through comparison with laboratory data, and good agreement between them was confirmed.
116 研究論文(国際会議プロシーディングス)
共著
Failure prediction model of a rubble mound weir using distinct element method
Maeno,S., Kase,E.
Proc. 31st IAHR Congress

3304-3311
2005/09



Nature-friendly hydraulic structures such as a rubble mound weir have attracted attention in recent years. Therefore, it is important to establish a numerical model to predict a possible failure process. In this research the distinct element method, which is used for modeling the aggregate of discontinuous elements, is applied to model a failure process of the rubble
mound weir. Hydrodynamic forces acting on the rubble of the weir, such as: a drag force and a seepage force are required for the DEM calculation which was obtained by the flow analysis using VOF technique. It is confirmed that the numerical results using the proposed method can reproduce the movement of particles in the early stage of failure under a steady flow condition. The effect of an inter-particle contact angle of the DEM on the failure process of the rubble mound weir was clarified.
117 研究論文(国際会議プロシーディングス)
共著
Effect of rainfall hyetograph on pollutant loads
in an urban catchment area
N.Wada, Y.Tsuji
Proc. 10th Int. Conf. Urban Drainage

CD-ROM, 8 pages
2005/08



Field measurements and runoff analysis of stormwater in a small urban area were performed. The effects of rainfall hyetograph on the pollutant runoff process were examined. Excellent agreement between SWMM simulation and field data were found not only with the runoff discharge, but also with the concentration and washoff rate of nutrients. A response analysis of pollutant runoff was carried out for design storms of single-peaked triangular hyetographs with various durations and peak intensities. The results provide information useful in the management of sewage and river systems, such as in the design and operation of sewage treatment plants, planning of river restoration for increasing river self-purification capability, scheduling of road cleaning operations, land use planning, etc.
118 研究論文(国際会議プロシーディングス)
共著
Resident evaluation of a waterside environments
Wada,Y., Wada,N.
Proc. 10th Int. Conf. Urban Drainage

CD-ROM, 8 pages
2005/08



The advance of urbanization has brought rapid and large-scale changes to the landscape. Development has impacted the river basins and water circulation, thereby there are causing various problems due to changes in the volume of water in rivers and water pollution. In Japan, with the graying of society and the expansion of leisure time, people seek “ease of mind” and they are becoming more and more interested in the natural environments close to home. In this research we investigated extensively resident awareness of the waterside environment in City A and studied factors necessary for and important to future improvement of this environment based on analysis of: frequency of waterside utilization; differences in the impact of the waterside environment between those who are satisfied with the current state of the environment and those who are not; and functions people expect from the waterside. As a result, in order to realize a desirable waterside environment, water quality should be improved and rivers should be made cleaner, while facilities to enable residents to safely enjoy riversides should be constructed. To enhance utilization by residents, it is important to publicize those improvement projects that are implemented to make rivers more attractive.
119 研究論文(学術雑誌)
共著
費用効果分析による都市内河川整備の評価
和田安彦・和田有朗
土木学会論文集

No.796/ II-72, 81-92
2005/08



本論文では,都市内河川周辺住民に対する河 川意識調査により,住民の望む河川整備要因を把握した.その整備項目をもとに8つの整備案を立案し,コンジョイント分析による整備効果の解析を行った.さらに,整備案に対するライフサイクルコス トを定量し,コンジョイント分析の全体効用値を効果とする費用効果分析により今後の都市内中小河 川の環境整備の方向について検討を行った.因子分析にもとづく整備案より得られた結果,今後の河川整備方向として,水質,見た目の大幅な改善ができない場合には,快適 環境と 自然環境の向上を図れる広場を有した緑化護岸整備と 安全性を確保する街灯整備などが重要で、あることを明らかにした.
120 (MISC)総説・解説(学術雑誌)
共著
ステートオブジアーツ,水工学
辻本哲郎
土木学会誌

90/ 7, 80-81
2005/07




121 (MISC)総説・解説(学術雑誌)
単著
森は湖・貯水池を浄化するか?

森林技術

759, 2-7
2005/06




122 研究論文(学術雑誌)
共著
Evaluation of riverside environment from local inhabitants by factor analysis
Wada,N.
J.Environmental Information Science

33/ 5, 33-42
2005/03



In this research we investigated what advantages people who live near the water want to receive from their environment, and what sorts of improvements of the waterside they would like to see. To that end, we analyzed the images of the waterside environment held and the ideas about the need for improvement expressed, comparing city-dwellers who are satisfied with their waterside environment and those who are not satisfied. We also included age as a factor. The results of our analysis indicated that those who are dissatisfied find it difficult to gain any enjoyment of nature or come into contact with nature at the waterside near which they live, as compared with those who are satisfied. We also found that young people want to use the river area for sports and other physical exercise, while older people want to enjoy nature along the shore. These findings indicated that the waterside environment should be improved in various ways, including: improving the quality of the water ; constructing promenades that feature natural scenes and creating spaces where people can observe nature; and dividing the waterside into different zones according to use,i.e., for camping, water skiing or sports. It is also important to publicize progress in waterside improvements that are intended to make them attractive, because many citizens are not interested in their local rivers.
123 研究論文(学術雑誌)
単著
捨石水制が冠水した開水路流の二次元二層流モデル
南條雅志・石垣泰輔・前野詩朗
土木学会論文集

782/ II-70, 31-50
2005/02



石礫を用いた透過水制の水理設計を目的として水制周辺と内部の流動構造を検討した.捨石堰を越流・透過する一次元流れの解析モデルを拡張して,水制が設置された二次元開水路流の解析モデルを構築した.開水路と捨石多孔体からなる二層流を仮定し,流れの連続性と運動量保存を定式化した.水制内の運動量保存は,粒径や間隙率など材料特性を考慮した多孔体乱流の非線型抵抗則を用いて記述された.水制の越流部では,水制天端を通しての質量・運動量交換が考慮された.水制周辺の流速や水位の分布に関して数値解析と水理実験が比較され,本解析の妥当性が検証された.水理実験では計測できない水制内の流れや流体力の特性についても本解析によって情報が得られた.
124 研究論文(学術雑誌)
共著
水温躍層における貧酸素水の成長機構について
小谷英之・佐々木茂太・西口祐輝
水工学論文集

49, 1177-1182
2005/02



It was observed in a eutrophic reservoir that metalimnion was deoxygenated and kept anaerobic during heating season while hypolimnion was successfully aerated. It was investigated in this study what brought the metalimnion deoxygenation. The fact that dissolved oxygen decreased faster in the sidearm than in the main reservoir suggests that oxygen consumption by the sediments might be one of the deoxygenation mechanisms. The additional mechanism of deoxygenation is considered to be decomposition of organic matters that were densely suspended in the metalimnion. The field data suggested that dissolved nutrients, metals, organic matters, etc. were released from the bed sediments at which the anaerobic metalimnetic water was touching. This reduction process may generate horizontal intrusion of the anaerobic and polluted waters from the sidearm into the main reservoir.
125 研究論文(学術雑誌)
共著
都市流域の流出汚濁解析と負荷特性におよぼす降雨形態の影響
和田有朗・辻義和
水工学論文集

49, 1579-1584
2005/02



In urban areas where there is a high density of property, infrastructure and population, it is an urgent task to develop an engineering tool for predicting the quantity and quality of stormwater from the viewpoints of disaster prevention and preservation of the water environment. In the present study, a field measurement and a runoff analysis of stormwater in a small urban area were performed, and the effects of rainfall hyetograph on the pollutant runoff process were examined. Excellent agreement between the SWMM simulation and the field data were found not only with the runoff discharge, but also with the concentration and transporting rate of nutrients. A response analysis of pollutant runoff was carried out for design storms of single-peaked triangular hyetographs with various durations and peak intensities. The results provide information useful in the management of sewage and river systems, such as the design and operation of sewage treatment plants, planning of river restoration for increasing river self-purification capability, scheduling of road cleaning operations, land use planning, and so on.
126 研究論文(学術雑誌)
共著
個別要素法を用いた捨石堰の破壊予測
前野詩朗・加瀬瑛斗・菊池慶太
水工学論文集

49, 787-792
2005/02



Nature-friendly hydraulic structures such as a rubble mound weir have attracted researcher’s attention in recent years. Therefore, it is important to establish a numerical model to predict a possible failure process. In this research, the distinct element method which is used for modeling the aggregate of discontinuous elements is applied to model a failure process of the rubble mound weir. Hydrodynamic forces acting on the rubble-mound weir such as drag force and seepage force which are required in the calculation of DEM was obtained by the flow analysis using VOF technique. It is confirmed that the numerical results using the proposed method can reproduce the movement of particles in the early stage of failure under the steady flow condition. It is also clarified that the contact angle of DEM particles has a significant effect on the failure process.
127 研究論文(学術雑誌)
共著
Discharge through a permeable rubble mound weir
Maeno,S., Furusawa,T. and Haneda,M.
J. Hydraulic Engineering, ASCE

131/ 1, 1-10
2005/01



The hydrodynamics of a rubble-mound weir are theoretically and experimentally examined. This type of weir is considered to be environmentally-friendly, since its permeability allows substances and aquatic life to pass through longitudinally. By performing a one-dimensional analysis on a steady non-uniform flow through the weir, discharge is described as a function of related parameters, such as flow depths on the up- and downstream sides of the weir, porosity and grain diameter of the rubble mound, weir length, etc. A laboratory experiment is carried out to determine the empirical coefficients included in the analytical model. The theoretical solution of the discharge is compared with the experimental data to verify the analysis. It is confirmed that agreement between theory and experiment is satisfactory for a wide range of flow conditions. The present study makes it possible to apply the rubble mound weir for practical use as a discharge control system.
128 (MISC)その他記事
共著
台風0423号による水害
辻本哲郎,戸田圭一
土木学会誌

89/ 12, 27-29
2004/12




129 研究論文(国際会議プロシーディングス)
共著
Study on Flow Structure and Discharge over a Permeable Rubble Mound Weir
Maeno,S.
Proc. 4th Int. Symp. on Environ. Hydraulics and 14th APD-IAHR

2, 1801-1808
2004/12



In order to compute discharge over a permeable rubble mound weir, a one-dimensional analysis and a laboratory experiment were carried out. Assuming a two-layer flow con-sisting of a free surface flow over the weir and a turbulent seepage flow in the weir, one-dimensional momentum and continuity equations were formulated in order to analyze flow structure and discharge. The shear stress at the two-layer interface was evaluated by considering mass and momentum exchange between the open channel flow and the seepage flow. The analysis well reproduces longitudinal flow development well, and provides a solution of for discharge as a function of relating hydraulic parameters.
130 研究論文(国際会議プロシーディングス)
共著
Numerical simulation of the flow around a rubble mound weir
Maeno,S.
Proc. 4th Int. Symp. on Environ. Hydraulics and 14th APD-IAHR

2, 1809-1815
2004/12



Nature-friendly hydraulic structures such as a rubble mound weir have attracted attention in recent years. Therefore, it is important to establish the analytical model to analyze the flow around such a weir. The VOF method is used for modeling the flow around a trapezoidal porous weir and Porous Body Model is employed to describe a porous part of the weir. The treatment of the resistance force is also examined to express the difference of permeability of a porous weir. The numerical results show that the proposed numerical method can be applied to the flow around a porous weir.
131 研究論文(学術雑誌)
共著
住民の暮らしからみた水辺環境の評価
和田安彦・和田有朗
土木学会論文集

776/ VII-33, 83-95
2004/11



本研究では ,利用者の住民が望む水辺環境に必要な構成要因および望む方向性についてアンケート結果より検討した.その結果,今後の水辺環境整備の方向性は,水質浄化,河川美化を望む人が多く,年齢層別に活用できる ようゾーン分けを行い,スポ ツなどが行えるゾーンや自然を楽しみながら散策の行えるゾーンなど多目的に用意する必要がある.また,護岸整備において安全に河川にアプローチできる護岸整備が望まれている.さらに水辺環境管理活動への参加意思は,年齢が高くなるに従い高くなり,住民による保全活動を重視した河川管理を行うことが今後の水辺環境の利用及び保全において効果的である.
132 研究論文(学術雑誌)
共著
利用者からみた水辺環境の評価
和田有朗
環境情報科学論文集

18, 95-100
2004/11



本研究では,住民が望む水辺環境を整備するために必要な施設の構成要素および整備の方向についてアンケートに基づき検討 した.市民のイメージを因子分析およびクラスター分析を用いて解析した. その結果,清らかな流れや自然の豊かさなど快適性に関する整備を求める意見が多く,自然的要素を考慮 した環境整備が必要であることが明らかとなった.また,河川の護岸整備においては,安全に水辺へアプローチできる護岸整備が望まれている.
133 研究論文(国際会議プロシーディングス)
共著
Modeling of Thermosolutal Plume and Biochemical Processes in a Eutrophic Reservoir
Matsuo,M.
Proc. 5th International Symposium on Ecohydraulics

2, 803-807
2004/09



In the hypolimnion of a eutrophic reservoir, an inclined plume was generated along an anaerobic benthic layer through a biochemical reaction between the water and sediment interface. The plume transported heat and heavy polluted water into the bottom layer and brought characteristic water quality structure such as meromix-is at the fall overturn, formation of inversely stratified temperature structure, and heavy contamination of the bottom layer. Considering the physical and biochemical processes, a numerical model was developed in order to simulate seasonal variations in water quality.
134 研究論文(国際会議プロシーディングス)
共著
Contamination of reservoir hypolimnion caused by chemically stratified flow
Kanda,T.
Proc. 3rd Civil Engineers Conference in the Asian Region

59-63
2004/08



A field measurement was performed in a reservoir to investigate a special mechanism of hypolimnetic contamination. The author focused his attention on an inclined plume generated on a sloping benthic layer whose driving force is the specific density difference between the salty water in the benthic layer and the ambient water. The salty water is produced through a bio-chemical reaction or reduction of bed materials that are exposed to anaerobic ambient water. It was found that the plume transports a significant amount of dissolved materials such as metals, nutrients, organic and inorganic matter, etc. This is how the polluted water was collected from the anaerobic benthic layer and transported down to the bottom layer. The phenomenon found in this study is a new contamination mechanism has never been discussed in previous studies.
135 (MISC)総説・解説(その他)
単著
播磨地方における川づくりの事例

土木学会関西支部講習会「歴史と地域に学ぶ川づくり」テキスト

45-55
2004/06




136 (MISC)総説・解説(大学・研究所紀要)
共著
捨石で構築された堰・水制の水理機能
石垣泰輔・前野詩朗・竹原幸生・江藤剛治・南條雅志・羽根田正則
京 都 大 学 防 災 研 究 所 年 報 

47/ B, 581-600
2004/04



捨石を用いた透過型の堰や水制の実用設計を目指して構造物の水理特性を検討した。捨石構造物内外の流れや構造安定性などの基本特性を水理実験によって明らかにし,非ダルシー型多孔体乱流の抵抗則を適用することによって,捨石構造物周辺の流れを解析した。水理実験との比較から解析モデルの妥当性が検証され,捨石構造物の水理設計への見通しを得ることができた。
137 研究論文(学術雑誌)
共著
傾斜堆積面からの嫌気的溶出により発生する化学成層流と栄養塩溶出・酸素消費の解析
金井健史・東野誠
土木学会論文集

754/ II-66, 75-90
2004/02



富栄養化により貧酸素化した底泥堆積層においては,嫌気的な溶出が水中の物質濃度と密度を増加させる.堆積層表面が勾配を有する場合には溶出成分の過剰密度によって傾斜プルームが発生し,境界層の流れの構造を変えるために底泥からの物質溶出もまたその影響を受ける.堆積層系のリンと鉄の酸化還元反応・吸脱着ならびに好気的分解による酸素消費を考慮し,水中でのリン・鉄・溶存酸素の保存則や運動量保存則を定式化して,壁面密度流と嫌気的溶出に関する水系-堆積層系の連成解析が行われた.溶出水塊の密度,堆積面の傾斜角,周囲水の流速と溶存酸素濃度,堆積層のリンと鉄の濃度などが溶出フラックスや酸素消費速度におよぼす影響を明らかにした.
138 研究論文(学術雑誌)
共著
透過型水制の周辺・内部の流れに関する実験と解析
石垣泰輔・前野詩朗・南條雅志・池松健
水工学論文集

48, 799-804
2004/02



A permeable groin constructed with natural stones would be a nature-friendly river structure with minimum negative impact on natural environment. For making suitable design of the structure, hydrodynamics of the flow inside and around the permeable groin was investigated in the present study. Physical models of the permeable groin were installed in an open channel with various dimensions, porosity and rubble diameters. A numerical model was developed in order to simulate a two-dimensional flow field both in the open channel and the porous body. A flow resistance inside the groin was formulated by applying a non-Darcian formula that has already been verified in the authors' previous study on a rubble mound weir. Effects of grain diameter, porosity, geometry of the groin on the flow structure and flow force were discussed based on the experimental and the numerical data.
139 研究論文(学術雑誌)
共著
捨石堰周辺の流況解析
前野詩朗・森永智・菊池慶太
水工学論文集

48, 829-834
2004/02



Nature-friendly hydraulic structures such as a rubble mound weir have attracted attention in recent years. Therefore, it is important to establish the analytical model to analyze the flow around such a porous weir. The VOF method is used for modeling the flow around a trapezoidal porous weir and Porous Body Model is employed to express a porous part of the weir. The treatment of the resistance force is also examined to express the difference of permeability of a porous weir. The numerical results show that the VOF method can be applied to the flow over an impermeable trapezoidal weir. Moreover, the flow of the porous part was approximately obtained by using the Porous Body Model.
140 研究論文(学術雑誌)
共著
貯水池の有機汚濁と深水層における逆転水温層・高塩分水塊の消長について
神田徹・石川浩
土木学会論文集

740/ II-64, 45-62
2003/08



富栄養化した貯水池において,底層に高い電気伝導度(塩分)と逆転水温勾配をともなう熱塩成層が観測された.暖海水や高濃度温泉水の流入によって形成される「異常水温成層」とは異なり,深水層の貧酸素化にともなう底泥からの嫌気的溶出と熱塩傾斜プルームが成因であることが明らかになった.深水層における熱塩成層の季節変化,貧酸素化にともなう深水層への熱・水質輸送過程が「熱塩循環モデル」によって検証された.熱塩輸送が深水層の有機汚濁を促進するとともに深水層の重力安定度を増加させて周年にわたる部分循環状態を維持し,底層に汚濁水を滞留させることが示された.ここで検出された熱塩循環は,これまで一般に認知されてきた汚濁負荷とは別に考慮しなければならない新たな水質汚濁機構である.
141 研究論文(学術雑誌)
共著
捨石堰を越流・透過する流れの構造と流量解析
前野詩朗・羽根田正則・古澤孝明
土木学会論文集

740/ II-64, 131-142
2003/08



捨石堰を越流・浸透する流れの流量を算定するために水理実験と理論解析を行った.流れを粗面開水路流と乱流多孔体流れからなる二層流と仮定し,上下層間の運動量交換を考慮して二層界面での内部抵抗を評価した.捨石堰内の運動量保存は被圧多孔体乱流として定式化された.様々な捨石粒径,間隙率,堰の高さ・長さ,水深の条件下で水理実験を実施し,水面形,捨石堰内外の流速,捨石の抵抗力など水理諸量の特性について実験と理論との良好な一致を得た.さらに関連パラメータの関数として流量の理論解が得られ,実験結果との比較・検証がなされた.本研究成果は,堰による流量・水深制御,さらに堰の破壊条件評価など実用的な構造物設計に応用することができる.
142 (MISC)総説・解説(その他)
単著
Restoration Project of the Chikusa River in Cooperation with Local Inhabitants, Government and Scientists

Proc. 3rd World Water Forum, Session of Water and Cultural Diversity, Session 5, WATER AND CULTURAL DIVERSITY

201-211
2003/08



A river restoration project in the Chikusa River Basin has been started in cooperation with local inhabitants, government and scientists. So far, river works have been carried out with a focus mainly on flood disaster prevention, but little attention has been paid to the natural and social environment. In addition to flood control, water use and the hydrospheric environment are very important aspects to the river restoration that should be taken into account. In order to lead the project in the right direction, we need more information on the nature in the basin, and need to understand the historical background of the culture, industries, agriculture, forestry and lives of the people. Through the investigation of these subjects, we can learn what people expect from the river, how people are involved in the river system, and how people live within the natural environment of the basin. In this report, the author intends to show the natural environment, human activity and engineering problems with respect to flood protection and water use, historical views of industries and cultures, recent river restoration programs conducted by the local government and inhabitants, etc. Based on various data, the way the restoration program should be worked out is discussed, as is what we can learn from past experiences so that we can apply them to the river works.
143 研究論文(学術雑誌)
共著
透過性構造物内部の流れに関する画像解析-流速と乱れの計測-
南條雅志・竹原幸生・江藤剛治・花谷清明
可視化情報

23/ Suppl.1, 111-114
2003/07



Recently, permeable river structures such as a rubble mound weir attract attention from an environmental point of view. A permeable structure minimizes negative impact on natural environment compared to conventional solid structures made of concrete and steel. This type of weir purifies water through aeration as well as provides passage of aquatic lives in the longitudinal direction. In order to evaluate these environmental functions, it is necessary to analyze internal flow in the structure.
In this study, flow fields in a rubble-mound weir were visualized by adjusting refractive index between solid-fluid phases. The flow velocity and turbulence are measured from image analysis, and the flow properties inside rubble-mound was analyzed. The present research will be useful in making hydraulic design of a permeable rubble mound.
144 研究論文(国際会議プロシーディングス)
単著
A numerical and experimental study on biochemically produced double-density structure in a eutrophic reservoir

International Conference on Fluxes and Structures in Fluids

101-104
2003/06




145 研究論文(学術雑誌)
共著
貯水池の富栄養化にともなう熱塩成層のモデル化
松尾昌和・香川健一・斉藤敦
水工学論文集

47, 1237-1242
2003/02



Reservoir eutrophication brings deoxygenation of hypolimnetic water and high concentration of metal, nutrients and dissolved materials are released from the bed sediments. Production of dissolved materials then increases fluid density along the reservoir bed. On a sloping boundary, the heavy water mass generates an inclined thermosolutal plume that transports the polluted water and heat energy from the shallow layer to the deep layer. The authors found the plume is responsible for generation of stable salty water with inverse thermal stratification in the bottom layer. The present study is to develop a model that can reproduce eutrophication as well as seasonal variation of the thermal and salinity structure produced by this mechanism. The model is Lagrange-type based on a one-dimensional DYnamic Reservoir Simulation Model, DYRESM. The original model was modified so that the thermosolutal convection and chemical and biological processes can be taken into consideration. The present model was verified through comparison between the simulation results and the field data.
146 研究論文(学術雑誌)
共著
神戸地域の市街化にともなう大気環境の変化
玉井昌宏・松下晃己
水工学論文集

47, 13-18
2003/02



Local climate change with urbanization in Kobe City area was investigated by using a turbulence closure model. Wind and temperature fields in air were computed with respect to the present ground conditions in the city and those of fifty years ago when the city area was less extended. Parameters of ground surface such as albedo, geometrical roughness and water content from the old age were estimated from correlation between land use and categories of governmental districts. The analysis showed that urbanization in the last fifty years brings local warming such air temperature increases of 1 to 2 degree in daytime and 0.5 to 1.0 degree in nighttime. Change was also confirmed in the daily variation of sea-land breeze in the planetary boundary layer up to 3,000 to 4,000m in elevation form the ground surface.
147 研究論文(学術雑誌)
共著
捨石堰の破壊機構のモデル化
前野詩朗・森永智・大西利典
水工学論文集

47, 781-786
2003/02



Nature-friendly hydraulic structures such as a rubble mound weir are attracting attention in recent years. Therefore, it is important to get the information about the destruction mechanism of a rubble mound weir. In this point of view, this study was carried out to investigate basic hydraulic characteristics in a failure stage of the rubble mound weir. As a result, it is clarified that the velocity at downstream weir slope, the seepage force in the rubble mound weir and gradient of downstream weir slope have an effect on the failure of the weir. Furthermore, the authors proposed a destruction model on the first stage failure of the rubble mound weir and confirmed the validity of the destruction model.
148 (MISC)総説・解説(その他)
単著
閉鎖水域の環境水工学の歩みと展望

水工学シリーズ

02-A-6, A-6-1-A-6-20
2002/09




149 研究論文(国際会議プロシーディングス)
共著
Discharge through a permeable rubble mound weir
S.Maeno, T.Furusawa, M.Haneda
Proc. 5th International Conference on Hydro -Science & -Engineering

CD-ROM, 10 pages
2002/09



A rubble-mound weir is proposed as a nature-friendly structure for controlling river flow. By performing a one-dimensional analysis, discharge through the weir is formulated as a function of hydraulic parameters such as flow depths at the upstream and downstream the weir, porosity and grain diameter of rubble mound, weir’s geometrical dimension, etc.. A laboratory experiment is carried to determine the unknown model parameters and to compare the measurement with the analysis. The theoretical solution agrees quite well with the experimental data for wide range of flow conditions. The present study makes it possible to apply the rubble mound weir for practical use as a discharge control system.
150 研究論文(国際会議プロシーディングス)
共著
Hydraulic characteristics of a rubble mound weir and its failure process
Maeno,S., Morinaga,S. and Ohnishi,T.
Proc. 5th International Conference on Hydro -Science & -Engineering

CD-ROM, 7 pages
2002/09



Various impermeable weirs (e.g.; concrete weir) have been constructed across the river for the purpose of water utilization. But they intercept river flow and cause negative influences to self-purification of river water and the ecosystem of aquatic biota. Considering these environmental problems, nature-friendly hydraulic structures made of natural materials are attracting attention in recent years. In this study, the authors have focused on a rubble mound weir as one of the nature friendly structures. However, available information of the rubble mound weir is insufficient at the moment. This study was carried out to investigate basic hydraulic characteristics of the rubble mound weir.
151 研究論文(学術雑誌)
共著
捨石堰の破壊時の水理特性
前野詩朗・森永智・大西利典
応用力学論文集

5, 657-664
2002/09



Nature-friendly hydraulic structures made of natural material are attracting attention in recent years. In this point of view, the authors have investigated basic characteristics of a rubble mound weir and clarified the discharge-water-level characteristics and so on. This study was carried out to investigate basic hydraulic characteristics in a failure stage of the rubble mound weir. As a result, it is clarified that the velocity at downstream weir slope and the seepage force in the rubble mound weir have an effect on the failure of the weir.
152 (MISC)その他記事
共著
産官学協同の授業づくり-プロジェクト授業の試行-
土木学会関西支部特定事業幹事会
土木学会誌

87/ 12, 80-83
2002/06




153 (MISC)総説・解説(その他)
単著
社会・自然環境のうつりかわり,人と川の関係

土木学会関西支部共同研究グループ報告書

13 pages
2002/05




154 研究論文(学術雑誌)
共著
A free convection plume generated on a sloping boundary with constant buoyancy
Fujita,I., Takahashi,T. and Yabumoto,K.
J.Hydroscience and Hydraulic Engineering

20/ 1, 167-178
2002/05



Momentum and scalar transports were investigated in a flow system where an inclined plate is heated up with a constant temperature to generate a thermal plume on a sloping boundary. The plume is a free convection in that there is no external mass and momentum supply. The purpose of the system is to simulate an anaerobic reservoir hypolimnion on a sloping bed where heavy solutes such as ionic metals and inorganic nutrients released from the bed flow down the sloping boundary toward the lower region of lake bottom. Temperature and velocity profiles were measured by using thermocouples and a particle-tracking velocimetry, respectively. By means of flow visualization using fine tracer particles and a sophisticated PTV algorithm the velocity measurement proved to be accurate even in such a sluggish density current. A theoretical analysis was made to obtain solutions for flow and buoyancy fields assuming the flow to have a self-similar structure along the longitudinal direction. The theory and experiments agreed closely in respect to velocity and buoyancy profiles as well as to the longitudinal evolution of the plume. The flow analysis is an effective method for estimating transport of water quality caused by biochemical reaction in the anaerobic benthic layer.
155 (MISC)その他記事
共著
将来構想特定幹事会活動報告-大学教育WG-
将来構想特定幹事会
将来構想特定幹事会報告

16 pages
2002/04




156 (MISC)会議報告等
共著
工学教育検討委員会[FD-WG]報告
三輪康一 阿部重夫 沼昌宏 小川和彦 薄井洋基
神戸大学工学部,平成13年度FD活動報告会資料集


2002/03



工学教育検討委員会における前年度までのFDワーキンググループの活動を踏まえて,平成13年度は,神戸大学工学部にふさわしい教育制固とそのフィードパックの方法を提案することを課題に活動をすすめた.そのためにまず国内外の大学で教育評価 とそのフィードバックがどのように行なわれているかを調査し,その結果に基づいて工学部で実施すべきフィードパック法の検討を行なった.
157 研究論文(学術雑誌)
共著
曝気形態と貯水池深層水質との関係について
神田徹・大成博文・森口昌仁・松尾昌和・松尾克美
水工学論文集

46, 1091-1096
2002/02



An in-situ experiment on hypolimnic aeration has been carried out in a eutrophic reservoir. Micro air bubbles were discharged into the anaerobic hypolimnion to supply oxygen and improve water quality. The system has been in operation since March in 1999. The aerator unit was so designed that the hypolimnic water is aerated without disturbing thermal stratification. At the beginning of the experiment, however, because of unsuitable design of nozzle structure, the aerator generated unexpectedly large bubbles and promoted vertical mixing. Although the hypolimnic water was aerated due to aerobic water entrained from the epilimnion, this was not the hypolimnic water aeration what we expected. The aerator structure was then modified to prevent macro-bubble generation and the hypolimnic water was successfully aerated without destratification. After all, in the course of the experiment the reservoir has experienced three different dissolved oxygen regimes, i.e. (1) no aeration, (2) aeration with vertical mixing, (3) aeration with little vertical mixing. The present study is to discuss how the dissolved oxygen affects hypolimnic water quality by comparing the field data from the three different DO regimes. The results provide useful information in designing an aeration system as a countermeasure against hypolimnic water eutrophication.
158 研究論文(学術雑誌)
共著
捨石堰の「水位-流量」特性を規定する水理量
前野詩朗・古澤孝明・羽根田正則
水工学論文集

46, 487-492
2002/02



A rubble mound weir is designed to be a discharge controlling system in nature-friendly river works. This allows streamwise transports of aquatic lives as well as of physical and chemical substances. A riverine ecological web might be better preserved by such a river structure than by conventional types of weirs and dams that completely block streamwise immigration of aquatic lives. For both purposes of flood control and water reservation, a “discharge-water-level” relationship is required in order to perform the structural design. In the present study flow discharge through the porous weir is experimentally examined in laboratory test flumes. The experimental condition is limited to a submerged flow in which the water surface is kept below the weir’s crown. The flow discharge is correlated with hydraulic parameters such as water levels, weir’s porosity and length, etc.. Performing a one-dimensional flow analysis, the discharge is successfully described as a function of the parameters. The agreement between the theory and experiment is satisfactory. The present theory would provide a design guideline of the structure.
159 研究論文(学術雑誌)
共著
自然石を用いた堰の水理特性
前野詩朗・森永智・大西利典
水工学論文集

46, 493-498
2002/02



Various impermeable weirs (e.g.; concrete weir) have been constructed across the river for the purpose of water utilization. But it intercepts river flow and causes negative influences to self-purification of river water and ecosystem of aquatic biota. Considering these environmental problems, the nature-friendly hydraulic Structure made of natural material is attracting the attention in recent years. In this study, the authors focused on a rubble mound weir, and examined its basic hydraulic characteristics. Laboratory experiments were carried out to investigate the flow characteristics for the permeable and impermeable weirs. Investigations were also conducted for pore water pressure distributions through permeable weir and its failure process. This study suggests that permeable weir made of natural gravel would be better than impermeable weir concerning to the control of environmental problem.
160 研究論文(国際会議プロシーディングス)
単著
k-e turbulence modeling on density current flowing into a stratified reservoir

Proc. Intnl Conf. "FLUXES AND STRUCTURES IN FLUIDS"

145-147
2001/06



Many lakes and reservoirs in industrialized countries are suffered from water quality troubles such as eutrophication and long-term suspension of turbid substances. Since it is urgently required to take some countermeasures against them, prediction and assessment of water quality are one of the most important missions of civil engineers.
Although several reservoir models were devised and applied in water quality prediction, their attentions are mainly paid on mean-flow convection rather than turbulent transport. The latter, however, plays a significant role in cases such as; (1) high discharge of flood inflows run into a reservoir; (2) strong natural convection promotes a full-depth scale overturn; (3) a strong wind shear stress is imposed on an air-water interface and generates intensive mixing and upwelling of hypolimnic water, etc.. In these phenomena, the flow structure is affected not only by turbulence but also by density stratification.
The authors have successfully performed turbulence modeling in respect to the latter two processes, say (2) the penetrative convection (Murota and Michioku, 1988) and (3) the wind-induced mixing (Michioku, Tsujimoto and Miyamoto, 1993). The present paper is to perform a k- turbulence modeling in order to examine the process (1), i.e. river inflow dynamics in a stratified reservoir. Hydrodynamic interaction between the inflow water mass and the stratification of ambient water is of special interest in the present analysis.
161 研究論文(国際会議プロシーディングス)
共著
A field measurement of vertical entrainment due to nocturnal cooling in a stratified reservoir
T.KANDA
Proc. 6th International Workshop on “Physical Processes in Natural Waters”

139-142
2001/06



A surface mixed-layer, SML, in lakes and reservoirs is exposed to atmospheric disturbances such as wind shear stress and surface heat exchange that promotes turbulent mass transport in a water body. The latter especially plays a significant role in winter, since the surface cooling generates whole-depth scale natural convection that lifts up polluted water from bottom to surface. A water temperature measurement was carried out in a reservoir in order to examine turbulent properties of penetrative convection during winter nights. A convective velocity was successfully evaluated by conditionally sampling temperature time series. Entrainment coefficient and profiles of turbulent heat flux were compared with those from atmospheric convective boundary layers and from water tank experiments.
162 研究論文(学術雑誌)
共著
浮力一定の傾斜面から発生するプルーム
藤田一郎・高橋俊之・藪本圭一郎
水工学論文集

45, 967-972
2001/02



A plume generated from a sloping boundary of constant buoyancy was investigated. The flow configuration is to simulate an inclined benthic layer in which dissolved constituents are released due to anaerobic reduction from a lake bottom. This process is supposed to play an important role in a eutrophication in lakes and reservoirs. A theoretical model was developed assuming a self-similar flow structure. Solutions for buoyancy and velocity fields were successfully obtained. A laboratory experiment was carried out in a thermal-buoyant plume system. A steady plume was experimentally reproduced by heating up a sloping plate to a constant temperature. Temperature and velocity were measured by means of thermocouples and particle-tracking velocimetry, respectively. The agreement between the analysis and the experiment was quite satisfactory not only in their vertical profiles but also in their streamwise development. The analysis enables us to quantitatively estimate water quality transport caused by the plume in a reservoir benthic layer.
163 研究論文(学術雑誌)
共著
捨石堰における通過流量特性
福岡達信・古澤孝明
水工学論文集

45, 391-396
2001/02



The authors propose a rubble-mound-weir as a flow control structure of nature-friendly. It is expected that this type of weir would allow aquatic animals traveling along the streamwise direction, while conventional structures made of metal and concrete completely block their movement along a river. Once a discharge flow-depth relationship is identified, even such a permeable structure could have a function to impound water and control river flow. The present paper is to examine hydraulic characteristics of the rubble-mound-weir. Main focus was placed on an open channel flow running through the weir. The system is a turbulent flow running through porous media that is connected to an open channel flow at the up- and downstream direction. Water surface profiles and a discharge-water depth relationship were experimentally and theoretically investigated.
164 研究論文(学術雑誌)
共著
マイクロバブルによる富栄養貯水池の水質改善工と浄化効率
神田徹・大成博文・森口昌仁・松尾昌和・白澤静敏・松尾克美
水工学論文集

45, 1201-1206
2001/02



Micro-bubbles were discharged into the lower layer in a eutrophic reservoir in order to aerate and purify the contaminated waters. Water quality has been monitored in the last 1.5 year after starting the system operation. In the first one year, the water body was more mixed and overturned by the micro-bubble aerator than we expected, although the aerator was originally designed so that only the lower layer water is aerated with minimum vertical mixing. The reason of such significant mixing was that high amount of unexpected and undesirable macro-bubbles were generated at the nozzle's outlet. Nevertheless, it was found through measurements of nutrients, metals, DO, etc. that the water quality was much more improved than before and the water purification system has been running quite well. In the last July, generator's structure was modified for preventing macro-bubble generation and then micro-bubbles were generated more efficiently. Water quality change after improvement of the system were also reported.
165 研究論文(国際会議プロシーディングス)
単著
A preliminary experiment on reservoir water purification by pumping and showering the lower layer water onto the surface layer

Proc. 12th Congress of APD-IAHR

4, 1275-1284
2000/11



A water purification system was designed as a countermeasure against reservoir eutrophication. The facility is such that anaerobic cold water is pumped up from the lower layer of a thermal stratification and showered onto the water surface. It is expected that the system could suppress algae activities by cooling down the surface water as well as aerate the anaerobic water while it is showering. After plunging into the air-water interface, a plume is generated due to buoyancy difference from the ambient water. This study is to experimentally examine mixing properties of the plume by using a physical model. Through normalization of the observed plume’s profile with width and intrusion depth scales, the plume was found to have a self-similar profile independently of time. Dimensionless forms of the scales were formulated as functions of a dimensionless time. Combination of the two dimensional analysis made it possible to predict time-dependent dispersion behaviors of the plume.
166 研究論文(国際会議プロシーディングス)
単著
Regional distribution of thermal stratification properties in Japanese limnological waters

Proc. 4th Intnl. Conf. On Hydroscience and Engineering

CD-ROM
2000/09



Thermal régimes in Japanese limnological waters such as lakes and reservoirs are investigated from a hydrodynamic point of view. Focus here is placed on seasonal variation patterns of thermal properties such as stratification behaviors, heat exchange at an air-water interface, etc.. Dependency of lakes’ thermal regimes on meteorology and water depth dimension is analyzed by making a mixed-layer modeling. Surface heat exchange is formulated as a function of an equilibrium temperature. Applying field data of the equilibrium temperature to the model, maps of lakes’ thermal properties are produced and thermal régimes in Japanese inland water areas is discussed.
167 (MISC)速報,短報,研究ノート等(大学,研究機関紀要)
共著
マイクロバブル技術によるダム貯水池の水質浄化法の開発
松尾克美・前田邦男・大成博文
電力土木

288, 36-40
2000/07



W型およびM型と呼ばれるマイクロパフ守ル発生装置システムを開発し,それらを,ダム貯水池表層に発生したアオコの発生制御実験および下層の無酸素水域における溶存酸素回復実験に適用した。その結果,ダム貯水池表層では,W型装置システムによって ,アオコの発生が抑制された。また,ダム貯水池下層では,M型装置システムによって,上下流の広い範囲で無酸素水域が大規模に減少し,さらに,貯水池全層において水温分布の変化が観察された。
168 研究論文(国際会議プロシーディングス)
共著
Inclined wall plume generated by buoyancy flux from sloping bed
Matsushita,K., Takahashi,T.
Proc. 5th Intnl. Sympo. On Stratified Flows

2, 697-702
2000/07



An inclined plume generated by a buoyancy flux on a sloping boundary was examined. The flow is a free convection; a driving force is a pure buoyancy flux from the slope surface and no mass flux discharge is supplied. The present system is to simulate a sloping benthic layer in a reservoir surrounded by anaerobic waters in which dissolved matters are released from the bed due to anaerobic reduction. A heavy and salty water mass is then produced right above the bed and gravitationally runs down the sloping bed. The plume transports dissolved constituents such as nutrients and metals to deep region, which promotes eutrophication in the bottom layer. This flow configuration was reproduced in a laboratory experiment. For technical convenience of flow generation and measurements in the experimental model, buoyancy was supplied by heat flux instead of salinity discharge. Through measurements of velocity and buoyancy profiles, it was confirmed that the flow has a self-similar structure. A theoretical analysis was also performed and the solutions of velocity and buoyancy show good agreement with the experiment. Streamwise development of the plume was well reproduced by the theory as well.
169 研究論文(学術雑誌)
共著
壁面上の一様な浮力フラックスによって発生する傾斜プルームのPTV計測
藤田一郎・高橋俊之・藪本圭一郎
可視化情報

20/ suupl.1, 91-94
2000/07



A PTV analysis was performed to examine flow structure of a plume that is generated by buoyancy flux discharge imposed on an inclined boundary. Fine nylon particles of 60m in diameter and 1.02 in a specific weight were used as tracers. The flow field was illuminated by a laser light sheet. Velocity profiles and streamlines from the PTV were compared with a theoretical solution that was obtained from a self-similarity flow analysis. They agreed quite well and the present visualization and the PTV were verified to be a useful measurement tool for such a slow and stratified flow. Performance of the tracer particles was rather satisfactory, despite it is usually difficult to keep tracer particles buoyantly neutral in a stratified flow system.
170 研究論文(学術雑誌)
共著
底面からの浮力溶出によって傾斜面上に発生するプルームの実験と解析
松下研一・高橋俊之
土木学会論文集

649/ II-51, 49-60
2000/05



富栄養化した湖沼・貯水池においては,底泥から各種の物質が嫌気的に溶出し,比重の大きな高濃度層が底泥堆積層上に形成される.底面が傾斜している場合にはプルームによって,高濃度の栄養塩や有機物が水域の深部へ輸送され集積する.本研究では,このような「溶出プルーム」を実験モデルによって再現し,流速・浮力の分布,流程方向の発達特性が検討された.また,流れの自己相似性を仮定して溶出プルームの理論解を得た.理論に基づいて実験値を規準化した結果,流速・浮力分布の相似性が確認されるとともに,プルームの流程方向の発達過程が理論的に説明された.これより,嫌気的溶出によって発生するプルームの水質輸送量の評価が可能となった.
171 (MISC)会議報告等
単著
研究討論会,セッションⅢ報告

沿岸域

12/ 2, 4-5
2000/03




172 研究論文(学術雑誌)
共著
マイクロバブル・エアレータによる貯水池の水質浄化実験
神田徹・大成博文・西川孝晴・松尾克美・木戸崇博
水工学論文集

44, 1119-1124
2000/02



A water purification system was developed and installed in the lower layer of a eutrophic reservoir. A preliminary test was conducted in order to examine its performance. The aerator generates fine air bubbles of several ten micro millimeters, so-called micro-bubbles. Dissolved oxygen, temperature, electric conductivity and other water quality items have been measured in every two weeks after starting the micro-bubble aeration in March 1999. Despite continuously operating the system, total amount of dissolved oxygen in the reservoir has decreased so far, from which the air discharge is estimated to be less than oxygen consumption due to decomposition. Nevertheless, DO concentration in the lower layer is higher than that observed in the last four years, while DO in the surface layer has been kept less than that in the last four years. These results suggest that the system functions for aerating water body to some extent, except that the air discharge is not sufficient for complete aeration, yet.
173 研究論文(国際会議プロシーディングス)
共著
Nutrient transport due to heat-salt convection in a eutrophic reservoir
T.KANDA
Proc. 28th Conf. IAHR

CD-ROM, 8 pages
1999/08



A reservoir investigated is seriously eutrophicated and shows a stable double-density stratification of heat and salt. The bottom layer is highly contaminated with dissolved nutrients and ionic metals, which brings significant salinity there. The impounded water has never been overturned over the years because of its heavy bottom water. Another characteristic feature is that an inverse temperature gradient is kept in the bottom layer throughout whole year. The resultant temperature and salinity fields show a complicated double-density structure. A field measurement was carried out in order to examine how heat-salt convection is involved in the bottom water eutrophication. The field data suggest the following hydrodynamics. Heavy water mass with high salinity is produced along the reservoir bed by anaerobic reduction of sediments. The heavy water with high concentration of nutrients, ionic metals and other dissolved materials then gravitationally goes down the bed slope, in other words, inclined plumes are generated along the sloping reservoir terrain. The plumes transport not only salinity but also heat from the warm upper layer. This could be a major mechanism of heat-salinity integration in the reservoir bottom. Water quality troubles due to the bottom water eutrophication could be minimized if some technical countermeasures would be devised for controlling the heat-salt convection.
174 研究論文(学術雑誌)
単著
貯水池底層水の水面散布に関する基礎実験

応用力学論文集

2, 685-690
1999/08



Performance of a new wate1 quality improvement system in a reservoir is experimentally examined by using a hydraulic model. The facility is such that anaerobic and polluted bottom water is pumped up and showered on the water surface. Although some projects of this system are running in several reservoirs, their performance are not well known. The target of this study is to find how the discharged water is transported in a reservoir and how much water quality mixing is expected to occur. In order to focus on hydrodynamics of the system, fresh and salt waters are used as working fluids to simulate warm surface water and cold bottom water, respectively. Hydrodynamic behavior of the diffusing plume are examined based on a dimensional argument. The result would provide information in developing a high-performance system for reservoir water purification.
175 研究論文(学術雑誌)
共著
Flow resistance in an open-channel with an alternative riffle-pool arrangement
Takemoto,O., Hirota,M.
J.Hydroscience and Hydraulic Engineering

17/ 1, 87-101
1999/05



For creation of a natural river environment, a channel restoration producing variety of f low fields is much appreciated in recent yea s. A typical way of such works is arranging structures such as riffles, pools, islands, and vegetation along a river course. After restoration works a t tent ions should be paid on ecological or environmental changes in a river system. Additionally, f low resistance has to be carefully evaluated f or prevent ion of flood disasters, because this type of river works absolutely increases channel's roughness. The present study deals with f low hydrodynamics in open channels in which riffles and pools are alternately and regularly arranged a long a flume. I n laboratory experiments, measurements were made with respect t o f low resistance, water surf ace profiles and velocity vectors. A d rag force coefficient was experimentally formulated as f unction of geometrical parameters of the riffle-pool model. This was applied to a one-dimensional analysis for evaluation of f low resistance. The friction coefficient computed by the method was well correlated with the experimental da ta.
The• present study helps us in designing river channel structures from a hydrodynamic point of view. It should be kept in mind that only the creation of a nature-friendly river ecosystem is sometimes dangerous; the restored channel should function as a flow conveyer of high flood.
176 研究論文(学術雑誌)
共著
貯水池での水温計測に基づく内部波・自然対流の抽出
神田徹・道奥康治・石川勝久
水工学論文集

43, 1049-1054
1999/02



Reservoir water temperature was measured simultaneously at vertical multi-points using a thirty-channel thermistor chain. Data were collected every 10.5-second in order to detect even short time-scale motions. The objective is to make investigation on internal waves and natural convective motions that are much responsible for turbulent energy transfer as well as for water mass t ran sport. Intern al wave propagation was examined by filtering time series of water temperature and a cross-correlation analysis. A propagation diagram in a space- time coordinate system successfully described scales, modes and propagation characteristics of in tern al waves. Natural convection was investigated by analyzing dataset collect d during winter nights. A conditional sampling, VITA-Variational Interval Time Averaging- was applied to detect organized motions due to nocturnal cooling. From conditionally averaged time series of temperature, a velocity scale of natural convection was obtained, which well agreed with the Deardorff’s velocity scale. Entrainment rate and vertical turbulent heat flux were evaluated, which were well correlated to those found in small-scale experiment al models.
177 研究論文(学術雑誌)
共著
熱塩循環による貯水池底層での熱と栄養塩の集積機構
安田篤司・松下研一・高橋俊之
水工学論文集

43, 1055-1060
1999/02



A reservoir under investigation has very characteristic structures of density and water quality, nutrients and dissolved materials are highly concentrated in a bottom layer and water temperature is inversely stratified. A fundamental study is carried out in order to examined how thermosolutal convection is involved in producing the water quality structure and in reservoir eutrophication. A governing process is assumed as follows. Organic matters in the bed material s are reduced under anaerobic condition and dissolved into impounded water. Heavy water mass containing dissolved materials or salinity is then produced along the reservoir bed, which generates inclined plume along the reservoir bed slope. The plume transport s heat and dissolved material s from shallow to deep regions along the slope. Heat and salinity are finally accumulated in the deepest region to build up a very stable heat-salt stratification. In order to verify the assumed mechanism heat-salt convection is experimentally and numerically examined in a two-dimension al reservoir model. A buoyancy flux is imposed on the bed surface for simulating the anaerobic plume generation. The inclined plume promotes heat and mass transportation along the bed and finally produces high concentration of heat and salt complex there. The heat­ salt convection is found to be much responsible in bottom water contamination in a highly eutrophic reservoir.
178 (MISC)速報,短報,研究ノート等(学術雑誌)
共著
ドイツ南西部における河川改修:その目的と経過(和訳担当)
ギュンター・ハートマン,アンドレアス・ディートリッヒ
多自然研究

40, 3-7
1999/01




179 研究論文(大学,研究機関紀要)
共著
取水構造物における局所洗堀特性
遠山直樹
神戸大学大学院自然科学研究科紀要

17-B, 39-50
1999/01




180 研究論文(大学,研究機関紀要)
単著
サーマルサイフォンの流動解析

神戸大学大学院自然科学研究科紀要

17-B, 51-56
1999/01




181 (MISC)速報,短報,研究ノート等(学術雑誌)
共著
生物工学護岸(Biological Engineering Method, BEM)の強度について(和訳担当)
アンドレアス・ディートリッヒ
多自然研究

39, 14-17
1998/12




182 (MISC)その他記事
単著
ヨーロッパの東西を結ぶ国土軸「マイン-ドナウ運河」
Schillinger, J.
土木学会誌

83/ 7, 33-36
1998/06




183 研究論文(学術雑誌)
共著
浅水部・深水部が交互に配置された開水路流の抵抗特性
竹本修・廣田宗明
水工学論文集

42, 955-960
1998/02



In recent years, so called "near-nature river works" are made in many river channels in order to create a suitable hydrospheric environment and ecosystems. The channel is required not only to provide good water environment but also to transport water mass without any hydraulic engineering troubles. In the present paper a fundamental experiment was carried out to examine an open channel flow resistance and characteristics, where simplified models of riffles and pools are alternatively arranged along the channel. The friction factor is correlated as a function of longitudinal interval of riffles, approaching angle of the riffle element and other hydraulic parameters of riffles and pool's geometry. It is expected the present research work to be a useful measure to determine river bed dimensions, so that a river channel design might be optimized to construct a best cross section not only for water environment but also for hydraulic functions of river channel.
184 研究論文(学術雑誌)
共著
Gravitational Stability of Thermal-Chemical Stratification in a Reservoir
Kanda,T., Nishikawa,T., Higashino,M, Itoh,T, Ishikawa,K.
J.Hydroscience and Hydraulic Engineering

15/ 2, 41-48
1997/12



A water quality measurement was carried out in a eutrophic reservoir where a double-density structure of chemical-thermal stratification was found. Vertical profiles of temperature, dissolved oxygen and electric conductivity were measured with portable field devices. Water samples were collected from four different levels and their water qualities such as metals, nutrients, organic matters and so on were examined in a laboratory. The measurements were carried out every month for the last two years. It is a striking feature of this reservoir that temperature near the bottom is inversely stratified throughout a year; the bottom water contains extraordinary high concentration of solutions, although there is no local source of salinity; and the water body has never been overturned in the last few years. The field data suggest that dissolved and suspended materials are so highly concentrated near the bottom that the double-density field is always kept overstable there. This is a reason why the reservoir water has not experienced a full-scale over turn even in a cold winter season.
185 (MISC)会議報告等
単著
Formation Mechanism of a Multi-Density Structure Consisting of Heat and Dissolved Materials in a Eutrophic Reservoir

Proc. 6th Forum of Research Works, Environmental Balance of Water Systems in Megaloplis -- in Cases of Beijing and Osaka Bay Area, Monbusho International Scientific Research Program --- Joint Research ---

6, Ⅶ/99-106
1997/11



Based on water quality measurements in a stratified reservoir, it is discussed how thermal Structure and dissolved oxygen concentration affect water quality behavior. The field measurement shows the reservoir has a multi-density structure consisting of temperature and material concentrations. The water body is so stable that no overturning has taken place even in winter, which makes the bottom water anaerobic and very eutrophic. It is found that shortage of dissolved oxygen is mostly responsible for highly concentrated organic and non-organic compounds in the reservoir bottom.
186 研究論文(大学,研究機関紀要)
単著
Maps of Lakes' Thermal Regimes in Japan

Memories of Faculty of Engineering, Kobe University

44, 15-32
1997/11



Thermal régimes in Japanese lakes are investigated from a limnological point of view. Focus here is placed on seasonal variation patterns of a lake’s thermal properties such as thermal stratification behaviors, surface heat exchange, heat transfer in water body. Dependency of thermal properties on meteorology and lake’s depth dimension is analyzed by applying a mixed-layer model. Meteorological conditions concerning surface heat exchange are approximated by using an equilibrium temperature. Applying field data of equilibrium temperature to the model, maps of lakes’ thermal properties are composed and thermal environment in Japanese inland water areas is discussed.
187 研究論文(学術雑誌)
共著
成層流風洞における対流境界層乱流の条件抽出
PlateE., Kaiser,R. and Rau,M.
土木学会論文集

579/ II-41, 67-82
1997/11



任意の風速・温度分布の成層流を再現できる新型風洞によって対流境界層を再現し,流れの乱流計測と条件付き解析を行った.温度時系列を検出信号としてVITA法により秩序構造を条件抽出し,プルームによる熱・運動量輸送特性を検討した.1) 接地表層では対流プルームによる強い高温上昇流(warm updraft)と壁面乱流が卓越し,低温下降流(cold downdraft)はゆるやかで,そのスケールは小さい,(2) 混合層では,急速な高温上昇流(warm updraft)によって大部分の熱・運動量が輸送され,低温下降流(cold downdraft)の輸送量は小さい,(3) 連行領域では,上層へのプルームの貫入(penetrative convection),すなわち低温上昇流(cold updraft)が主に貢献している,などの特徴が明らかにされた.
188 (MISC)会議報告等
共著
Damages in River and Water Systems after the Great Hanshin Earthquake
Kanda,T.
Proc. the second Japan-China Bilateral Symposium on Safety and Environmental Engineering

95-100
1997/10



The "Great Hanshin (Osaka and Kobe) Earthquake" recording 7.2 in magnitude hit Kobe and Osaka metropolitan area on January 17 in 1995 and brought serious damages on river and water systems. In this article, disasters are briefly reviewed and reconstruction of the systems are discussed from an engineering point of view. Most of the damages are concentrated in a so-called “Hanshin Area” which is a coastline region between Kobe and the west of Osaka City. The shaded area in Fig.1 shows the most severely damaged regions where seismic motions larger than Magnitude 7 are recorded. Kobe is the biggest city in this region and about 1,500,000 people are inhabited. The downtown of Kobe is stretching along a narrow coastline band from west to east, which is bounded by 900m high mountain in the north and by the Osaka Bay in the south, respectively.
189 (MISC)会議報告等
共著
Conditionally Averaged Turbulent Structure in A Stratified Flow Wind Tunnel
Plate,E.,Rau,M., Kaiser, R. and Thaeter,J.
Proc. "Klimaanalyse fuer die Stadtplanung" 2nd Japanese-German Meeting

232-239
1997/09



Turbulent structure of a convective boundary layer (CBL) was examined by performing a wind tunnel experiment. Because a thermal plume significantly affects air mass transport in a CBL, the wind tunnel should be operated in a way that not only a long-time average of flow structure but also an organized flow fields might be similar between a model and a prototype. In order to examine an organized flow structure, a VITA (variable interval time averaging) method is applied for conditionally sampling a dataset from a wind tunnel experiment. The data analysis informed us interesting features of turbulent heat and mass transport process in a CBL. Turbulent field in a CBL consists of several characteristic flow regimes; in a surface layer, predominant warm updraft and weak cold downdraft are respectively found inside and outside of a thermal plume; in an entrainment zone, cold updraft associated with negative turbulent heat flux is frequently observed.
190 研究論文(国際会議プロシーディングス)
共著
Water Quality Behaviors in a Reservoir Having Anaerobic Heavy Bottom Layer Coupled with Inverse Temperature Gradient
Kanda,T., Itoh,T., Ishikawa,K., Higashino,M.
Proc. 27th Conf. IAHR

1, 100-105
1997/08



Based on water quality measurements in a stratified reservoir, it is discussed how thermal structure and dissolved oxygen concentration affect water quality behavior. The field measurement shows the reservoir has a multi-density structure consisting of temperature and material concentrations. The water body is so stable that no overturning has taken place even in winter, which makes the bottom water anaerobic and very eutrophic. It is found that shortage of dissolved oxygen is mostly responsible for highly concentrated organic and non-organic compounds in the reservoir bottom.
191 研究論文(学術雑誌)
共著
底部に逆転水温層を有する部分循環貯水池の水質構成に関する研究
神田徹・伊藤達平・西川孝晴・石川勝久・東野誠
土木学会論文集

572/ II-40, 33-48
1997/08



対象とする貯水池は,底層で物質濃度が高く,水温勾配が逆転しており,また年間を通じて貧酸素水塊が安定に維持される部分循環貯水池である.この特徴的な水温・水質構造の形成要因と水域の富栄養化現象との関連性を明らかにするために,多項目の水質指標を計測・分析した.底層付近では鉛直下方に水温が増加し不安定な水温勾配を呈するにもかかわらず,底層水塊が通年的に滞留している. 水質観測より,貯水池底層から下層には,逆転水温勾配の密度欠損量を補償するに十分な高濃度の溶解性物質・浮遊物質が含まれることが明らかになった.鉄・マンガンなど金属成分は底層が貧酸素化した他の水域でも観測されるように高濃度を呈するが,その重量百分率は比較的小さく,底層水の密度構成に寄与する主成分はカルシウム・強熱減量などであった.貯水池水の水質分析に基づいて水質輸送過程を考察し,水質構造の形成要因,富栄養化と水質分布との関連性を実証的に明らかにした.
192 研究論文(国際会議プロシーディングス)
共著
A Flow Structure over Upwelling Producing Structure in an Oscillatory Flow Both With and Without Stratification
Tsujimoto,G., Nishide,H.
Proc. 7th Intnl. Offshore and Polar Engineering Conf.

7, 149-155
1997/05



Numerical calculation of the flow field over the upwelling producing structure in an oscillatory flow is conducted using the k-e turbulence model. Particular emphasis is on the flow field with or without stratification. The characteristic phenomenon such as the vortex formation was simulated. Irrespective of the value of Ri, the density interface will be destroyed when the height of the upwelling producing structure is higher than that of the density interface. Also with decreasing KC number, the separated vortex with intense vorticity is formed and a fast residual flow is seen near the upwelling producing structure through the experiment.
193 研究論文(学術雑誌)
共著
カオス解析による河川水温予測の試み
木村貢司
水工学論文集

41, 605-610
1997/03



Water temperature of a small river basin is predicted by applying a chaos analysis. Embedding observed data vectors generated from the data, a trajectory space is reconstructed and chaotic behaviors of time series are examined. Temperature time series is predicted, by applying a linear prediction scheme proposed by Sano and Sawada. The present analysis is verified by applying it to describe the logistic mapping function which is known as one of dynamic chaotic processes and whose governing equation is already known. Through comparison between the field data of river temperature and the analysis it is investigated how long prediction duration is possible and how much dimension of observed data vectors is necessary for water temperature prediction with desired accuracy. The present method is expected to be a useful measure for prediction of hydrological phenomena governed by some non-linear deterministic processes.
194 研究論文(大学,研究機関紀要)
共著
Thermal Structure and Quality Characteristics of Reservoir Water with Inverse Temperature Gradient
Kanda,T., Miyamoto,H., Higashino,M. and Ishikawa,K.
Memories of Faculty of Engineering, Kobe University

43, 75-80
1996/12



A field measurement of water quality is carried out in a reservoir in which the bottom water body shows high concentration of chemical and biological materials and very poor in dissolved oxygen. In addition, its temperature is relatively higher than the middle layer throughout a year, which means that the temperature gradient there is always unstable, while the layer is maintained stable. From the water quality measurement, it is shown that the bottom layer fluid has enough amount of materials to compensate the density defect due to the inverse temperature gradient. Because of such a stable multi-layered structure, the reservoir has never been overturned, so far. However, it could bring serious water quality troubles, once drastic change of meteorological and hydrological conditions would drive full scale overturning and mix up the bottom layer fluid to the surface one day in future. In this study, water quality behaviors and countermeasures against water quality troubles are discussed based on the observed results.
195 (MISC)会議報告等
単著
Water Quality Behaviors in A Multi-Density Stratified Reservoir

Proc. 5th Forum of Research Works, Environmental Balance of Water Systems in Megaloplis -- in Cases of Beijing and Osaka Bay Area, Monbusho International Scientific Research Program --- Joint Research ---

5, Ⅵ/35-39
1996/11



A field survey of water quality in a reservoir was summarized in the last joint forum. Focus was placed on the formation mechanism of such a characteristic density structure that the bottom layer water shows unstable temperature gradient and its density defect is gravitationally compensated by highly concentrated dissolved and suspended materials. In the present article more attention is paid on profiles of each water quality component in detail. The water quality items considered here are COD, nutrient materials such as nitrogen and phosphorus, , pH (potential of hydrogen), metal components like iron, sodium, manganese and calcium, ORP (oxidation reduction potential), SS (suspended solids), IL (ignition losses), etc.. Through chemical examination of sampled waters it is quantitatively shown how these materials build up the density structure. It was found that ignition losses, calcium, suspended solids, iron and manganese especially show high concentration in the bottom layer and it makes the layer with inverse temperature gradient be stable.
196 (MISC)その他記事
単著
ドイツ・カールスルーエ大学水文・水資源研究室(IHW)

混相流

10/ 3, 304-308
1996/09



ドイツ・カールスルーエ大学水文水資源研究室(IHW)のエリック・プラテ教授(Prof. Erich Plate)のご厚意を得て、1996年7~9月の3カ月間アレクサンダー・フォン・フンボルト財団の奨学金援助のもとに、同研究室に滞在する機会を得た。カールスルーエ大学は工科系主体の大学であり、流体工学の諸分野でも世界をリードする研究が行われているためなじみの深い人も多くあろう。IHWは土木工学科に所属し水工学関連の様々な研究を行っている。本報では大学・研究室の紹介ならびに新型の成層流風洞を用いて行われている大気対流境界層の実験を報告する。
197 (MISC)総説・解説(学術雑誌)
単著
密度成層流パラメーターに関する用語の解説

混相流

10/ 3, 294-296
1996/09



海洋、大気、陸水域など地球上の流れの大部分は密度成層乱流であり、異なる流体相聞に浮力(密度)差を伴う混相乱流である。流れは「層」と同時に「相」を成している。多くは温度や塩分濃度差に起因する「液一 液」あるいは「気一気」混相流であるが、気温と湿度からなる大気成層流・海洋の砕波・水面での気体交換過程などの「気-液」混棺流や、濁度一水温などの「固-液」混相流のように異相の流体成分からなる混相流も存在する。後者では、浮力効果に加えて異相聞の相互作用が重要となるが、本文では浮力が支配的な前者の場合に限定して、主に浮力と乱流輸送力の比をあらわす成層パラメータ: チヤードソン数密度フルード数、について解説する。
198 (MISC)会議報告等
共著
Water Quality Measurement in A Reservoir with Unstable Temperature Gradient
Kanda,T.
Proc. 4th Forum of Research Works, Environmental Balance of Water Systems in Megaloplis -- in Cases of Beijing and Osaka Bay Area, Monbusho International Scientific Research Program --- Joint Research ---

4, Ⅴ/2-5
1996/06



A field measurement of water quality is carried out in a reservoir in which the bottom water body shows high concentration of chemical and biological materials and very poor in dissolved oxygen. In addition, its temperature is comparatively higher than the middle layer throughout a year,which means that the temperature gradient there is always unstable, while the layer is maintained stable. From the water quality measurement, it is shown that the bottom layer fluid has enough amount of materials to compensate the density defect due to 也e inverse temperature gradient. Because of such a stable multi-layered structure, the reservoir has never been overturned, so far. It could bring serious water quality troubles, once drastic change of meteorological and hydrological conditions would drives full scale overturning and mix up the bottom layer fluid to the surface one day in future. In the present article water quality behaviors and countermeasures against water quality troubles are discussed based on the field measurement.
199 研究論文(学術雑誌)
共著
貯水池内に流入する浮力水塊の挙動解析
藤川佳宏・不二秀人
水工学論文集

40, 561-566
1996/03



Dynamics of river inflow into a stratified reservoir is discussed by performing a k- e turbulence model analysis. Several types of density currents found in a stratified reservoir are numerically reproduced; (1) plunging inflow at the upstream end of a reservoir, (2) surface density current taking place when fluid density of inflow is smaller than the reservoir water, (3) density undercurrents in the case of inflow density being larger than that of the reservoir water, (4) interaction between a thermocline and the inflow water mass, etc. It is confirmed that every types of the flows are successfully reproduced by the k- e turbulence model. Some of the results are compared with the previous laboratory experiments and satisfactory agreements between the analysis and the experiments are obtained. The authors believe that some turbulence model should be taken into consideration in modelling reservoir hydrodynamics, which would be powerful tool in predicting reservoir water quality.
200 研究論文(学術雑誌)
共著
底部に不安定成層を有する貯水池の水温・水質解析
神田徹・西川孝晴・東野誠・伊藤達平・石川勝久
水工学論文集

40, 601-606
1996/03



A field survey is carried out in order to examine water quality behaviors and thermal structure in a eutrophic reservoir, where very distinctive features are found in water quality profiles. Although temperature gradient is dynamically unstable in the bottom layer, thermal stratification has never been overturned even in a severe cold winter. On the other hand, electric conductivity is extraordinarily high in bottom layer to compensate density defect due to inverse thermal stratification. This suggests that there might be high concentration of dissolved materials and nutrients which are supposed to be originated from the reservoir bottom. In addition, dissolved oxygen is very poor in bottom layer. Based on the field surve.it is investigated what kind of mechanism works to construct such a characteristic profiles of water qualities.
201 研究論文(学術雑誌)
共著
PTVのための粒子画像抽出法に関する検討-粒子マスク相関法について-
江藤剛治・竹原幸生・久野悟志
水工学論文集

40, 1051-1056
1996/03



Some algorithms for particle identification in PTV, which are classified in a category ”particle mask correlation method", are presented and test ed. A typical brightness pattern of a particle image is referred as a particle mask; it is placed on an image plane and correlation coefficient between the particle mask and the image is calculated; the particle mask is scanned on the plane with the calculation of correlation coefficient; the small subareas with high correlation value indicate central areas of particle images.
202 研究論文(学術雑誌)
共著
PTVのための新アルゴリズムの開発
竹原幸生・江藤剛治・村田滋
土木学会論文集

533/ II-34, 107-126
1996/02



PTVのための新しいアルゴリズムを開発した画像中の多数の粒子の自動追跡のためにカルマンフィルターとχ2乗検定による自動粒子追跡アルゴリズムを提案した追跡途中で現れた粒子に対する粒子の情報を推定するためにドゥロネ三角形網を用いた内挿法を提案した.ビデオカメラを用いた3次元PTVのために,透明平面壁を透した水中粒子の3次元位置の計測法を再検討した.これらを熱対流場の計測等に適用した.
203 (MISC)会議報告等
単著
Damages on Sewage Works during the last Hanshin-Awaji Earthquake

Proc. 3rd Forum of Research Works, Environmental Balance of Water Systems in Megaloplis -- in Cases of Beijing and Osaka Bay Area, Monbusho International Scientific Research Program --- Joint Research ---

3, Ⅳ/11-14
1996/01



The Great Hanshin-Awaji Earthquake brought damage in sewer systems in the Osaka-Kobe Metropolitan Area, which significantly affected not only water balance but also water environment in this area. This chapter shows summary of the damages in the sewer systems and discuss their engineering problems.
204 研究論文(大学,研究機関紀要)
共著
貯水池底層水の水面散布による水質改善の実験
神田徹
神戸大学大学院自然科学研究科紀要

14B, 15-21
1996/01




205 研究論文(大学,研究機関紀要)
共著
冬季循環期における水温構造の日変化に関する集中観測
神田徹・東野誠・伊藤達平・石川勝久
神戸大学大学院自然科学研究科紀要

14B, 33-40
1996/01




206 研究論文(大学,研究機関紀要)
共著
底部に逆転水温層を有する貯水池の水質観測
神田徹・東野誠・伊藤達平・石川勝久
神戸大学大学院自然科学研究科紀要

14B, 41-48
1996/01




207 研究論文(大学,研究機関紀要)
共著
Internal Waves in A Two-Layer Density System with A Finite Thickness of Thermocline
Kanda,T., Itoh,T.
Memories of Faculty of Engineering, Kobe University

42, 71-94
1995



It is theoretically examined how the density profile affects internal wave dynamics. Considering a density field in which the upper and lower layers are divided by a thermocline of a finite thickness, a linear wave theory is developed to describe internal wave motions generated there. The density model employed is a so­called ”Holmboe’s density model” which can describe various types of density profiles; from a well-defined two-layer system to a weakly or continuously stratified system. Internal wave propagation, flow fields and spatial variation of density fields are analytically reproduced and discussed by applying the density model
208 研究論文(学術雑誌)
共著
海底構造物による均質及び密度成層化された振動流場の流況について
辻本剛三・西出浩明・坂本格・久野悟志
海岸工学論文集

42, 1056-1060
1995/11




209 (MISC)その他記事
共著
河川被害
福岡捷二・神田徹・日比野忠史
土木学会阪神大震災震災調査,第二次報告会資料

45-52
1995/03



兵庫県南部地震において河川堤防に大きな被災を受けたのは大阪湾から10km以内にある兵庫県と大阪府の沖積地内を流れる河川である。沖積層は、2万年程前から現在までにできた新しい地層であり、いわゆる軟弱地盤を形成している。今回の地震では、こうした軟弱地盤上に築造された堤防に大きな被害が集中している。調査を行った地区は13筒所であり、淀川、正蓮寺川、猪名川、藻川、神崎川、佐門殿川、中島川である。それらの地区の被害の形態は地震動の 強さ、地盤の状態及び堤防の構造によって 異なっていた。特に淀川本川河口域の高潮堤は、軟弱地盤上に造られており、甚大な被害となっている。震源地に近い武庫川や住吉JII(神戸市内河川)では、堤防天端の亀裂、沈下、すべり、高水敷の地割れ等の被害が起こったが、堤体の崩壊には至っていない。調査の時点(1995年2月1日-3日)では、大きな被災箇所は出水期の洪水に備えて緊急に復旧がなされていた。
210 研究論文(学術雑誌)
共著
半閉鎖水域における風成密度流の水質交換特性
辻本剛三・宮本仁志
水工学論文集

39, 805-810
1995/03



n order to examine mixing and turbulent mass transport processes in a wind-driven density current, a turbulence model analysis is performed. The system considered here is a 2-D semi-enclosed stratified basin whose downwind boundary is opened to an ocean; this flow system is analogous to the wind-generated currents in a small inlet, a bay, etc. Focus is placed on water mass exchange rate across the open boundary, which is found to have a strong functional dependency on the so-called ”overall Richardson number”. The present analysis give us useful information on what sort of hydrodynamic conditions could generate upwelling of polluted bottom layer fluid and water quality exchange between the basin and the external water area.
211 (MISC)その他記事
共著
Report by the river damage survey group
Fukuoka,S., Kanda,T., Hibino,T.
Preliminary report on the Great Hanshin Eqrthquake, January 17, 1995, Japan Society of Civil Engineers

177-187
1995/02



The Great Hanshin Earthquake did a great deal of damage to the embankments of rivers flowing through the alluvial areas of Hyogo and Osaka Prefectures within a 10 km range of Osaka Bay. Serious damage was concentrated on embankments constructed on weak ground consisting of alluvial deposits, the newest stratum formed during the past 20,000 years. The forms and degrees of damage in these locations differed according to the intensity of the earthquake motion, the ground state, and the embankment structure. Particularly serious damage was witnessed in embankments constructed on weak ground to protect against high tides i n the tidal reach of the Yodo River. The embankments of the Muko and Sumiyoshi Rivers (inside Kobe) near the focus of the earthquake suffered damage such as cracking, settlement, sliding of the levee crown, and fissures of flood channel, but the embankment structures themselves did not collapse. As of the date of this survey (Feb. 1 to 3, 1995), seriously damaged reaches had already been temporarily repaired in preparation for the wet season.
212 (MISC)速報,短報,研究ノート等(大学,研究機関紀要)
共著
布引貯水池における風の特性-神戸海洋気象台の風との関係-
神田徹・井口幸彦・前田浩之
建設工学研究所報告

36, 161-180
1994/11




213 研究論文(国際会議プロシーディングス)
共著
Wind-Driven Density Currents in A Semi-Enclosed Basin
Tsujimoto,G. and Miyamoto,H.
Proc.Fluid Mechanics and Management Tools for Environment


1994/11



Hydrodynamics of density currents generated by wind shear stress are analytically investigated. The objective is to examine how flow field and turbulence are affected by wind shear stress as well as by density stratification. A numerical analysis is carried out by using a modified k-e turbulence model. The computed entrainment rate is compared with previous laboratory experiments to verify performance of the model. Time-development behaviors of the mean flow, the density field and turbulent structure is discussed. The flow fields are predominantly governed by the two dimensionless parameters, i.e. the overall Richardson number and the aspect ratio of basin.
214 (MISC)総説・解説(その他)
単著
湖沼・貯水池における熱・物質輸送

水工学シリーズ

94-A-7, A-7-1~20
1994/08



近年,河川水系の水工学的課題は,「水量」から「水質」問題の克服へとその視点が移行しつつある.また,「水質」問題も,高度成長期の公害時代を経て,生態系のバランスに配慮した水環境の創造を標接する時代へと変遷し,水工技術者に求められる社会の要請はきわめて多様化・高度化している.湖沼・貯水池は河道部に比べ水面が広く水深が大きいため滞留時間が長く,池内・水表面・湖底などの境界と特異な熱/物質交換が生じて本川と異なる水理機能を有し,その結果,物質のみならず生態系をも大きく変化させる.池内の物質変換は,1)物理,2)化学,3)生物の各過程に大別される.このうち後二者を純数 理的に記述することは困難であり,丹念な実験・観測に基づき経験的に物質変遅過程を定式化することが必要である.水工学で専攻するのは主に1)の物理過程であり,水質輸送過程を合理的に再現し得る数理モデルを構築するべく物質収支の普遍則を見いだすことを目標に,多くの実験・観測・解析がなされている.本論では,湖沼・貯水池における熱・物質輸送現象の物理的側面に重点をおき,得られたこれまでの知見を総括する.いまだ未解決の検討課題も多くあり,主な成書・論文レビューにおける内容との重複を必要最小限にとどめることを考慮、して,本文では湖沼・貯水池の話題全てを網羅的に論ずるよりも主要な現象に焦点を絞り各論的な構成で稿をすすめる.
215 研究論文(学術雑誌)
共著
Internal Wave Fields in A Thermally Stratified Reservoir
Kanda,T.
Proc. APD-IAHR

9, 411-418
1994/08



A field survey is carried out in a thermally stratified reservoir to examine internal wave dynamics. Internal wave fields are measured by using a thermistor chain and its hydrodynamic proper ties are investigated. A theoretical model is developed in order to analytically reproduce internal wave motions consisting of wave components with various temporal and spatial scales. The pre sent theory is available to a stratified system with an arbitrary vertical profile of density. The theory shows well agreement with field data.
216 研究論文(学術雑誌)
共著
Analysis and Laboratory Experiment on Flow Fields and Bottom Sediment Transport around An Intake Structure
Proc.Modeling, Testing and Monitoring for Hydro Powerplants
Proc.Modeling, Testing and Monitoring for Hydro Powerplants

1, 201-212
1994/07



Sediment transport and local scouring process around an intake are examined analytically and experimentally. The intake structure considered here is a simplified one; an orifice gate with rectangular cross section through which a constant discharge of water is withdrawn. In order to evaluate flow fields as well as a criteria of sediment movement, a three dimensional flow analysis is performed. From the computed flow fields, criteria of bed materials transport around the intake is investigated. It is found that significant sediment movement could occur around the corner edge of orifice gate. The mobile area is strongly dependent on the sediment Froude number and the orifice height. To investigate local scouring process and sediment transport rate a laboratory experiment is also carried out. Fluid velocity, time-dependent behaviors of bed profiles and sediment transport rate are measured. Larger the Froude number and smaller the orifice height, the bed deepens more rapidly. The present study might be available in performance of suitable design for intake facilities in hydropower plants so that engineering troubles due to reservoir sedimentation could be minimized.
217 研究論文(大学,研究機関紀要)
共著
貯水池水の内部循環による水質混合促進
黒川純一良・吉田弘
神戸大学大学院自然科学研究科紀要

12B, 39-46
1994/03



受熱期に形成される貯水池の水温成層はその浮力効果によって池内の水質を滞留させ,様々な水 質問題の要因となっている.主な水質改善方策として,現在では,(1)選択取放水操作,(2)貯水池水の再曝気,などが実施されている.選択取放水は良質の水質からなる層が存在する場合において有効な方法である.これに対し,貯水池全体の水 質が悪化している場合には,再曝気のように水質を積極的に改善する方法を採用しなければならない.曝気装置として様々な形式のものが試行されているが,今のところいずれの方法が最も効果的であるかは明らかではない.曝気と同じく貯水池水質を強制的に改善するもう一つの方法として,池内の上層水と下層水を人工的に内部循環させ,鉛直方向の水質混合希釈を促進する工法が一部の 貯水池で実験的に稼働している.本研究ではこれを「内部循環工法」と称し,その水質混合促進効果を水理学的に検討する.
218 研究論文(学術雑誌)
単著
成層水域からの熱エネルギー抽出に関する試算

水工学論文集

38, 229-234
1994/03



In recent years development of high performance of heat pumps enables us to efficiently use the unused potential thermal energy naturally stored in water areas such as rivers, coastal waters, lakes, reservoirs, etc. The present study deals with thermal energy intake from a thermally stratified water bodies. Considering energy conservation in waters and intake systems, preliminary computation of possible Amount of thermal energy intake, average coefficient of performance (COP) of heat intake facilities and so on are carried out.
219 研究論文(学術雑誌)
共著
熱対流場における熱輸送と乱流構造に関する研究
島崎正則
土木学会論文集

485/ II-26, 27-36
1994/02



境界条件の異なる二種類の鉛直一次元熱対流場に乱流完結モデルを適用して温度ならびに乱流構造を解析する.平均温度・乱流構造の解について相似関数形を仮定し,乱流対流による熱・物質の輸送機構を解明する.対流層(外部)スケールおよび熱境界層(内部)スケールに基づいて本解析結果と既往の実験結果を整理し,両者の比較よりモデルの妥当性を検証する.特に,分子過程の影響を受ける墜付近の乱流輸送過程の再現性に重点をおいて乱流モデルを定式化する.
220 研究論文(学術雑誌)
共著
成層型貯水池に生起する内部波動の観測と解析
神田徹・重村誠一
土木学会論文集

485/ II-26, 65-73
1994/02



水温成層化した貯水池を対象に流速と水温の観測を行った.風応力によって誘起される内部変動を検出し,風向・風速と内部変動との相関性について検討した.観測された水温時系列のスペクトルなど統計諸特性を明らかにした.また,任意の密度分布を有する成層場に生起する内部波の基礎理論とフーリエ解析に基ついて,様々な水温分布状態 に生起する内部波を理論的に再現する手法を開発した.内部部波の時系列・スペク卜ル等に関して理論値と観測結果との比較・検討を行った結果,予測された内部波が観測値と良好に一致することを確認し,本解析の妥当性を検証することができた.
221 研究論文(大学,研究機関紀要)
単著
"Level-4" Turbulence Closure Model of Free Thermal Convection

Memories of Faculty of Engineering, Kobe University

40, 11-24
1993/11



A second order turbulence closure model is formulated to describe free convection field. The model employed here has a hierarchy structure consisting of different levels of approximation in closing the third order turbulent moments. The system considered here is a one-dimensional thermal convection field heated with a constant flux from below. It is investigated how exactly each level of closure assumption works in reproducing convective turbulence. The results computed from different version of models are compared each other and problems included in closure assumption are discussed.
222 研究論文(学術雑誌)
共著
自動粒子追跡アルゴリズムの改良と適用例
竹原幸生・江藤剛治・島崎正則
可視化情報

13/ Suupl. No.2, 115-118
1993/10



An automatic particle-tracking algorithm previously developed by the authors is improved for practical use and applied to measurements of velocity fields of thermal convection. The main part of the algorithm consists of the Kalman's filtering theory and the Chai-square test. The presented algorithm employs a generation method of Delaunay network to estimate initial values of velocity vectors of newly-appearing particle images in the source light sheet. The results of measurements are compared with those by Adrian et a l. by mean s of LDV and a theoretical prediction by the authors. It is shown that particle tracking velocimetry by the presented algorithm is applicable to measurements of flows with heat transfer.
223 (MISC)総説・解説(学術雑誌)
単著
Hydrodynamics in Lakes and Reservoirs

Res. & Practice in Hydraulic Engineering in Japan, Special Issue of JHHE

SI-1, 17-39
1993/09



Many Japanese lakes and reservoirs are loaded with engineering and environmental problems, among which (1) irrigation and fishery damages resulting from cold water outflows, (2) water pollution such as eutrophication process and (3) sedimentation and long suspension of turbid waters caused by sediment-laden flood inflows are the most serious ones. The last one might be one of the problems peculiar to our country, since many Japanese rivers have heavy sediment yield from their catchment areas. Reportedly, some reservoirs have experienced a number of such severe sedimentation disasters that their available volume capacity was completely filled up with sediment materials resulting from just one duration of precipitation. Chemical and biological processes also play important roles in such systems but focuses here are placed mainly on physical aspects, say ”the hydrodynamics". This chapter is composed of the three sections. First, basic research works on flow and mixing mechanisms in stratified lakes and reservoirs are briefly reviewed. Second, field case studies performed in Japanese lakes and reservoirs are discussed. Finally, the numerical models for describing and predicting heat and mass transport processes are presented. Other engineering problems such as flood flow control, sedimentation process, reservoir facilities operation, etc., should be referred to other papers, for instance, given by Aki(l989), Kikkawa(l 985).
224 研究論文(国際会議プロシーディングス)
単著
Thermal Regimes of Impounded Water Body Experiencing Summer and Winter Stratification

Proc. of the25th IAHR Congress

25/ 15, 457-464
1993/09



Long time scale meteorological variation such as global warming brings gradual changes in thermal environment around inland water areas. Reportedly, in some lakes in cold regions, there have been no ice formation in the last few winters, while their surface used to be covered by ice. We also notice other kind of environmental changes in hydrospheric areas, such as trend of water temperature increase and the resultant modification of lakes water quality. Since lakes and reservoirs are utilized for many purposes of our life, assessment and protection of thermal environment there are desperately necessary. The present work deals with annual variation of thermal regimes in temperature zone lakes which experience summer and winter stratifications, and is sometimes covered by an ice layer. An analytical model is proposed in or der to describe thermal structure, heat exchange at the water surface and ice covering and its melting processes. Effect of thermal meteorological conditions and lake depth scale on its annual thermal cycles are examined through the proposed analytical model. Focusing on medium-size water bodies with very small through-flow discharge, two and three dimensional processes and earth rotation effect s are not considered here.
225 研究論文(国際会議プロシーディングス)
共著
A Similarity Solution for Turbulent Free Convection
Kanda,T., Shimazaki,M.
Proc. Refined Flow Modeling and Turbulence Measurements

5, 367-374
1993/09



A turbulence model is developed to describe shear-free thermal convection field. Temperature and turbulence properties in two types of convection systems are examined and discussed. The analytical results are compared with some experimental data to verify the model.
226 研究論文(国際会議プロシーディングス)
共著
Turbulence Modeling of Double-Diffusive Convection
Plate,E.
Proc. Refined Flow Modeling and Turbulence Measurements

5, 753-760
1993/09



Thermosolutal convection is numerically examined by using a turbulence closure model. The double diffusion system considered here is a linear stable sal1nity gradient heated with a constant flux from below. A laboratory experiment is also performed to verify the model. Mean temperature, salinity and turbulent fields are successfully simulated by the model.
227 研究論文(国際会議プロシーディングス)
共著
Turbulence and Mixing in Stratified Shear Flows Driven by Surface Shear Stress
Tsujimoto,G., Miyamoto,H.
Proc. International Symposium on Turbulent Shear Flows

9, P207/1-4
1993/08



Stratified flows driven by surface shear stress are numerically examined by using a k-ε turbulence model. Our concern is a closed stratified system like lakes, reservoirs, land locked bays, etc., where wind shear stress acts on its water surf ace to generate baroclinic circulation and mixing. Time development of flow and density fields are numerically reproduced by the model. It is investigated how vertical mixing and bot tom water upwelling depend on density stratification.
228 研究論文(大学,研究機関紀要)
共著
取水口周辺の三次元流況と底質移動限界について
重光世洋
大阪産業大学論集,自然科学編

93, 17-23
1993/05



In recent years, there are many problems arise in most of the intake facilities constructed in reservoir due to local scour and entrainment of sediment flow into it, caused by the increase of sediment deposition. In order to decrease those troubles and also to make a suitable design of intake dimension, some analytical information is required before the performance of their practical countermeasures or for the planning of hydraulic laboratory studies. In this paper, the authors present a simple numerical analysis method to evaluate both of the velocity distribution in a condition of three dimensional flow and the critical initiation of sediment transport around the intake facilities. To evaluate the range of sediments initiation around the intake, the relations between the grain size Reynolds number and the grain size Froude number relating to the mean velocity of intake and the bottom velocity distribution in front of intake area had been proposed by use of the Sheilds’dimensionless critical tractive force and the critical sediment number.
229 研究論文(学術雑誌)
共著
貯水池の水温成層で観測される内部波動の解析
神田徹・小川修隆・重村誠一
水工学論文集

37, 331-336
1993/03



Field survey of internal wave motions in a stratified reservoir was carried out to examine their dynamics under the wind action on water surface. Stochastic analysis on internal behaviors in the stratified water body was performed to find out relationship between wind shear mechanism and internal wave reaction. A theoretical consideration based on the internal wave dynamics was also made to describe the internal wave motions. The observed modal structure and stochastic properties of wave fields were successfully reproduced by our analysis.
230 研究論文(学術雑誌)
共著
吹送密度流の流動・混合特性
辻本剛三・宮本仁志
水工学論文集

37, 293-298
1993/03



Two-types of wind-induced density currents are analytically examined by using a turbulence model. Discussed here are two-dimensional two-layer stratification systems; they are (1) a completely closed system in which both ends are bounded by fixed walls such as lakes and reservoirs and (2) an open system with no fixed boundaries like oceans. Flow and mixing regimes are related to the dimensionless governing parameters which are scaled in terms of the wind shear friction velocity, the horizontal and vertical dimensions of the water body and the buoyancy anomaly of the thermocline interface.
231 研究論文(学術雑誌)
単著
温帯湖の密度成層特性と熱サイクル

水工学論文集

37, 337-342
1993/03



In lakes and reservoirs we can gain high contrast of temperature differences between impounded waters and air as well as between surface and deep layer waters. They could be available for power generation, once we succeeded in developing efficient thermal power generation systems. As a feasibility studies for utilization of lakes thermal energy, the authors performed an analysis to describe density structure and annual thermal cycles in temperature zone lakes. In the analysis, winter stratification situations as well as freezing phase are successfully formulated, while they have never been considered in any lake models so far.
232 研究論文(学術雑誌)
共著
熱対流乱流場の自己相似解
島崎正則
水工学論文集

37, 343-348
1993/03



Turbulent thermal convection in a horizontal fluid layer system heated from below is analytically examined by using a turbulence closure model. Self-similarity functional forms for mean temperature as well as for turbulent terms are assumed to get their solutions. Two types of scaling are proposed; one is concerned with external parameters based on the convective layer depth; the other is so-called internal parameter scaling which are based on molecular processes in the conductive sub-layer. The solutions are compared with experimental results to verify our analysis.
233 (MISC)総説・解説(学術雑誌)
共著
貯水池水の蘇生をはかる;水資源開発公団”一庫ダム貯水池”の深層水エアレーションシステム
森川七生
土木学会誌

77/ 11, 12-15
1992/08




234 研究論文(学術雑誌)
単著
二重拡散対流におよぼす流体拡散性の影響

「ながれ」, 11巻別冊(第24回乱流シンポジウム論文集)

356-361
1992/07



Fluid diffusivity effect on double-diffusive convection is numerically examined by using the ”Level 2.5 ”turbulence closure model. The system considered here is a stable density gradient composed of lower diffusivity fluid with unstable buoyancy flux of higher diffusivity fluid being imposed from below. Two dimensionless governing parame­ters, i.e. ”double-diffusive Peclet number" and ”Lewis number", are found through dimensional arguments. Performance of a parametric analysis with respect to the two parameters shows us how fluid diffusivity affects double-diffusive mixing processes and its turbulent structure.
235 (MISC)総説・解説(学術雑誌)
単著
密度成層水域における乱れと鉛直混合現象

混相流

6/ 2, 132-148
1992/06



Research work concerning vertical mixing processes in stratified water areas is briefly reviewed. Attention is focused on vertical mixing phenomena which are found in the hydraulic engineering field, such as estuaries, lakes, reservoirs, land locked bays, etc. From the view point of the mixing mechanism, entrainment processes are classified into three categories, i.e., (1) shear induced entrainment (S­type), (2) entrainment due to eddy convection and diffusion in the mechanical stirring field (DM-type) and (3) entrainment due to thermal convection (DT-type). The turbulence structure and entrainment mechanism for each case are examined and discussed. Experimental and analytical work on entrainment relationships is shown for several types of stratified flow fields among which shear-free turbulence generated by an oscillating grid, stratified shear flows, wind-induced mixing and turbulent penetrative convection are included.
236 研究論文(学術雑誌)
共著
Parametric Analysis on Annual Variation of Surface Heat Exchange and Thermal Structure in Lakes
Kadoyu,K.
J.Hydroscience and Hydraulic Engineering

10/ 1, 77-94
1992/05



An analytical work is performed to examine the effects of lake depth and meteorological factors upon thermal regimes in lakes. Stratified temperature field is analytically described by means of a one-dimensional mixed-layer model. Surface heat flux is expressed by a simplified heat exchange relationship, where an equilibrium temperature with a sinuous function of time is introduced to describe the seasonal variation of meteorological conditions. In this case, we need not specify time-dependent functional form of surface heat flux, which is given as a solution of the analysis. Vertical mixing process is analytically described by the entrainment laws which are proposed in the author’s previous experimental study. Computed seasonal development of temperature field and surface heat exchanges are in satisfactory agreement with field data. Normalization of basic equations leads to two governing parameters, with which a parametric analysis is performed. Based on the analysis, lakes are classified into three categories; (a) stratified lakes (or thermo-dynamically deep lakes), (b) moderately-mixed lakes and (c) well­ mixed lakes (or thermo-dynamically shallow lakes).
237 研究論文(学術雑誌)
共著
乱流完結モデルによる熱塩成層場の乱流構造解析
Erich Plate
土木学会論文集

443/ II-18, 17-26
1992/02



乱流完結モデルを用いて熱塩対流の数値シミュレーションを行う.一定の濃度勾配を持つ線型密度成層の底面から熱フラッ クスを供給し,自然対流がもたらす鉛直混合と乱流 構造を解析する.平均濃度・温度について著者らの水理実験結果と解析との比較を行い,現象が良好に再現されていることを確認した.また,既往の実験的研究においては明らかにされていなかった熱塩成層場の乱流構造に関する新しい知見を得た.
238 (MISC)速報,短報,研究ノート等(大学,研究機関紀要)
共著
「過剰安定型」二重拡散現象の乱流モデル定式化と陰的差分法による数値解析法
Plate,E.
建設工学研究所報告

33, 95-114
1991/12




239 (MISC)速報,短報,研究ノート等(大学,研究機関紀要)
共著
潮位変化にともなう急変断面水路内の内部応答特性
長谷川憲孝
建設工学研究所報告

33, 115-126
1991/12




240 (MISC)速報,短報,研究ノート等(大学,研究機関紀要)
共著
貯水池の水温構造に関する調査研究
神田徹・真嶋政彦
建設工学研究所報告

33, 127-163
1991/12




241 研究論文(学術雑誌)
共著
Seasonal Thermal Cycle in Stratified Deep Lakes
Murota,A., Sakaguchi,S.
J.Hydroscience and Hydraulic Engineering

9/ 1, 11-26
1991/05



Focusing on the thermo-dynamic processes in deep lakes, the annual cycle of thermal structure is analytically considered. An integral mixed-layer model is formulated to analyze the stratification and destratification processes. It is found that the annual thermal cycle in deep lakes is divided into the following three thermal stages: (1) the former heating period: temperature stratification develops due to water surface heating, (2) the latter heating period: the wind-induced mechanical stirring overcomes the stabilizing effect of surface heat flux and the mixed-layer slowly deepens under the action of weak vertical mixing and (3) the cooling period: the vertical mixing is driven by the combined action of the wind-generated disturbances and the thermal stirring caused by natural convection. The cooling period is, furthermore, divided into the two sub-categories: the mechanical-stirring-dominant period and the thermal-stirring-dominant period.
242 研究論文(大学,研究機関紀要)
共著
Friction Effect on Internal Wave Motion in a Two-Layer Density Strata
Toriyama,K.
Memories of Faculty of Engineering, Kobe University

37, 55-69
1990/11



An experimental work an d an analysis were performed to examine the effects of wall and bottom shear friction on interfacial long wave motion in a two-layer f1uid system. Two types of experiments were carried out; the first one is on the free oscillating mode and the second one is concerning the forced oscillating motion, respectively. Increasing the friction forces, the free oscillation period becomes larger compared to that of the shear-free oscillation. Although the present one-dimensional analysis well describes qualitative aspects of the internal oscillation, it rather underestimates the wave period than the experimental data. The friction effect on the forced internal motion was also examined. It was found that dissipation of the internal wave motion due to friction becomes predominant around the resonant oscillating frequency.
243 研究論文(学術雑誌)
共著
水温成層の形成におよぼす水深・力学的外因の影響
角湯克典
水工学論文集

34, 175-180
1990/02



The annual cycle of surface heat exchange process and thermal structure in lakes were examined by performing a model analysis. The annual variation of the meteorological conditions were described in terms of annually varying equilibrium water temperature as a single harmonic sinusoidal function of time. The water temperature field was expressed by using an integral mixed-layer model and its stratification and destratification processes were evaluated by our developed entrainment laws. The present analysis enables us not only to get the thermal structure solution but also to analyze the surface heat flux or heat balance of the water body. We found dimensionless parameters which govern the annual variation patterns of thermal structure as well as surface heat exchange. Using these parameters, classification of thermo-dynamic phase in lakes was performed, in which three categories of lakes, i.e. stratified lakes (or thermo-dynamically deep lakes), moderately­mixed lakes and well-mixed lakes (or thermo-dynamically shallow lakes), are found.
244 (MISC)速報,短報,研究ノート等(大学,研究機関紀要)
共著
貯水池内に浮遊した濁水の排除工法に関する基礎的検討
吉田弘
建設工学研究所報告

31, 165-182
1989/12




245 (MISC)速報,短報,研究ノート等(大学,研究機関紀要)
共著
放熱期における池内水温構造の簡易解析法
山辺建二
建設工学研究所報告

31, 183-190
1989/12




246 (MISC)速報,短報,研究ノート等(大学,研究機関紀要)
共著
布引貯水池の水温変動に関する観測調査
神田徹・名手和巳
建設工学研究所報告

31, 261-287
1989/12




247 研究論文(国際会議プロシーディングス)
共著
An Analysis on Turbulent Field in Thermally Stratified System Generated by Composite Stirring
Murota,A., Kanda,T.
Proc. IAHR Congress

D173-D180
1989/08



When the wind stress and the destabilzing buoyancy flux of surface cooling simultaneously act on the water surface of lakes and reservoirs, complicated mixing phenomena take place due to the combined action of mechanical and thermal stirring. To simulate such a situation, the authors devised an experimental model in which the thermal stratification was modeled as a two-layer system the mechanical turbulence and thermal convective motions were driven by means of an oscillating grid and a bottom plate heater, respectively. We succeeded in experimentally formulating the mixing-law, which was applied to predict the thermal structure of practical reservoir. The present work is to theoretically analyze the turbulent structure in this system and examine the heat and mass transport process.
248 研究論文(学術雑誌)
共著
複合因擾乱によって生ずる水温・流速変動の特性
室田明・阪口進一
水工学論文集

33, 565-570
1989/03



Turbulent field induced by combined action of mechanical and thermal stirring is experimentally investigated. Turbulence is generated by means of an oscillating grid and plate heater both of which are installed at the bottom of a one-dimensional test tank. Dynamic effect of mechanical and thermal stirring on turbulent structure is examined by measuring fluctuating components of temperature and velocity. Temperature fluctuation decreases with increasing the relative intensity of mechanical stirring to thermal stirring. However, turbulent velocity is scarcely affected by the thermal stirring, in other words, the mechanical stirring dominates the fluctuating velocity field.
249 研究論文(学術雑誌)
共著
安定浮力流束が作用する場での振動格子乱流の数値シミュレーション
室田明・阪口進一
数値流体力学シンポジウム論文集

2, 407-410
1988/12



レイノルズ応力モデルやLarge Eddy Simulation (LES) 等, 言わばN-S方程式の原型に近いモデルほど乱流現象をより忠実に再現することができるが. その適用はごく単純な現象に限定されており,工学で対象となるような複雑な条件下の機々な流動現象を再現することは期待できない. 一方,現時点での愚も実用的な乱流モデルのーつとしてk-ε二方程式モデルが知られているが,局所等方性の仮定に基づいているために厳密には密度流現象への応用は不適切である.またここでは接動格子による力学的擾乱とヒーターによる浮力フラックスを上方から同時に受ける水混成層場での乱流-混合現象を対象とするがk-ε モデルはこのように平均的なせん断流がない場合の乱流現象に対しても破綻をきたす.そこで本研究では. 平均流がない自然対流場の乱れから複維な境界条件をもつ大気成層せん断流に至るまで多くの流れに対して適用実績をもつMellorとYarnadaの乱流完結モデル(以下M-Yモデルと略述)を導入し,乱流精造・混合特性・密度判骨造などに関する数値解析を行って実験結果との比較検討を行う.
250 研究論文(学術雑誌)
共著
安定な浮力フラックスの鉛直混合抑制効果
室田明・阪口進一
土木学会論文集

399/ II-10, 37-45
1988/11



During heating season, hydrodynamic behavior of the thermocline in lakes and reservoirs is predominantly affected by the combined action of the stabilizing buoyancy flux due to solar radiation and the mechanical stirring due to wind shear stress. The present paper examines the entrainment process in such a situation experimentally and theoretically. In a physical model, the oscillating-grid turbulence and the stabilizing buoyancy flux are simultaneously supplied to the upper surface of a two-layer thermal stratification system and the resultant entrainment process is investigated. The entrainment rate is related to an overall Richardson number. The turbulent structure is also analyzed by considering the energy balance in the present system. Applying the entrainment law, we get an analytical solution of the equilibrium condition where the mechanical disturbance energy just balances the stabilizing effect of the buoyancy flux.
251 研究論文(国際会議プロシーディングス)
共著
Dynamic Effect of Stabilizing Buoyancy Flux upon Entrainment Induced by Oscillating-Grid Turbulence
Murota,A.
Proc.APD-IAHR Congress

6, 177-184
1988/07



To obtain an understanding of thermocline behavior during heating season,the present study fundamentally examines stabilizing effect of insolation upon hydrodynamic properties of a wind-generated mixed-layer. A laboratory experiment is carried out in a physical model where oscillating-grid turbulence and stabilizing buoyancy flux are simultaneously imposed on the surface of a two-layer system. While Hopfinger and Linden 工982) performed a similar experiment in order to investigate thermocline formation process in an equilibrium state, the authors focus their attention on the vertical mixing process under the influence of stabilizing buoyancy flux. Introducing characteristic length and velocity measuring dynamic contributions of mechanical turbulence and stabilizing buoyancy flux to vertical mixing, the entrainment rate at thermocline is successfully formulated as a function of an overal1Richardson number. Combining the deduced entrainment law with the heat conservation equation, a mathematical model is set up to reproduce the growing of the mixed layer. The theory is verified with experiments. The present research should give much useful information in engineering aspects such as prediction and improvement of water quality within a surface layer, optimum withdrawal of surface warm water for irrigation and fishery, etc.
252 研究論文(国際会議プロシーディングス)
共著
Numerical Simulation of Turbulent Structure Produced by Combined Action of Mechanical and Thermal Stirring Using a Turbulence Closure
Murota,A.
Proc. Intnl. Symp. Refined Flow Modeling and Turbulence Measurements

3, 361-368
1988/07



To examine the mixing phenomena produced by the combined action of mechanical and thermal stirring, a numerical simulation was performed by using a turbulence closure model. Predictions of time development of temperature field as well as entrainment rate are in good agreement with our experimental results. Furthermore I we succeeded in reproducing turbulent structure in this work, although turbulent field could not be measured in our previous experiment.
253 研究論文(学術雑誌)
共著
複合因擾乱により誘起される鉛直混合現象の数値解析
室田明・口田光也
土木学会論文集

393/ II-9, 67-76
1988/05



To simulate the mixing process induced by the combined action of mechanical and thermal stirring, a numerical analysis is carried out by using a multi-equations approach of turbulence closure. The mixing properties, such as entrainment rate, thickness of the interfacial transition layer, fluctuation of thermal field and so on, are analytically reproduced by the present model, which shows a fairly good agreement with our experimental results. Additionally, the present analysis also succeeds in describing the turbulent field, e. g., turbulence intensity, turbulent energy flux balance, etc., which are much difficult to measure in laboratory and field observations. Combining the analytical work presented here with experimental and field information, we should be able to profoundly understand the mixing mechanism in such a situation.
254 研究論文(学術雑誌)
共著
停滞成層水域の水温構造年周変化に関する考察
室田明・阪口進一
水理講演会論文集

32, 263-268
1988/03



水面熱収支の年周期変動にともなう水温成層の応答特性を的確に予測することは停滞水域の水質挙動を考える上で工学的に重要であり{様々な角度から検討されてきた。しかし既往の解析においては最も重要な因子の一つである鉛直混合過程に関して十分な配慮がなされておらず,水質輸送量を評価する上で-合理性を欠いている。この点に着目して著者等は(i)水面への安定な浮力ブラックスの供給によって混合が抑制される受熱期,ならびに(ii)熱対流の擾乱によって混合が促進される放熱期,を対象として各々の場合に生起する鉛直混合現象を実験的に再現し,連行特性・内部変動特性を明らかにしてきた。本研究では以上の実験成果に基いて鉛直混合現象を定式化し,水面熱収支変動に伴う成層構造の変選に関す
る予測解析を行う。ただし,本研究は単なる水温予測手法の提案を目的とするものではなく,現象を支配する外的・内的因子の代表量によって現象を規準化し,水温構造の年周変化をあらわす普遍的な唯一解を求めることを主眼としている。さらに本解析を応用することによって停滞水域における鉛直混合現象の各種レジームを定量的に類型化し,そのカテゴリ一分類図を示す。
255 研究論文(学術雑誌)
共著
鉛直噴流の衝突による密度境界面での水質混合と混合水塊の挙動
室田明・黒川純一良・吉田弘
水理講演会論文集

32, 269-274
1988/03



近年、ダム貯水池で発生している富栄養化や長期濁水化現象は深刻化の一途をたどっており、今日大きく社会問題化するまでに至った観がある。これに対応する水質改善対策は次の2つに大別される。1つは貯水池内の密度成層を積極的に利用して、目標水質の水を得る選択取水の方法であり、もう1つは逆に鉛直方向の水質混合を人工的に促進し、貯水池水質を改善する方法である。本研究では、後者の立場に立ち密度境界面に対して直角に噴流を衝突させることにより生起する密度境界面での水質混合現象を対象として水理実験を行ない混合量の定量的評価と混合後の水塊の挙動特性について検討を行なった。まず、層体積の変化から混合量を評価し得るように、鉛直混合量に関する実験は小さな水平面積を有する鉛直一次元水槽を用いて準一次元的に行なった。次に実際現象に対応させるために、水平方向に十分な広がりをもっ三次元水槽で実験を行ない噴流衝突後の流動に視点をおいて、密度成層内における混合水塊の水平方向の伝播特性を解明するため、密度フロントの伝播に関する水理実験を行なった。これらの結果をもとに噴流の衝突・混合・水塊の伝播という一連の現象を総合的に評価し,貯水池内の密度成層の人工制御という観点から基礎的な知見を得たので報告する。
256 (MISC)総説・解説(その他)
共著
Some Aspects of Thermal or Turbidity Stratification in Japanese Reservoirs
Murota,A.
Proc.ROC-JAPAN Joint Seminar on Water Resources Engineering

33-47
1987/03



Serious problems related to water quality in reservoirs, e.g., cold-water damage to irrigation or fishery, retardation of turbid water, eutrophication of impounded water, etc., are frequently found in our country. Intending to understand the mechanism which governs these phenomena, the authors examine the hydrodynamic characteristics of water mass behavior in stratified reservoirs. Density stratification exerts a profound influence upon hydrodynamic process in reservoirs. We first discuss the annual cycle of thermal structure in reservoirs. Based on the field data as well as the experimentally derived information, we develop a practical model for the prediction of temperature fields, focusing on the vertical mixing process. The present model is capable of accurately reproducing field measurement of thermal structure. Second, normalizing the basic equations in terms of several scaling factors, we find the key parameters which govern the thermal structure in reservoirs. These parameters are then used to develop an analytic classification of Japanese reservoirs. Turbidity is another important water quality factor in the hydrospheric environment. We discuss the problem of long retardation of turbidity in reservoirs, with some examples of field data from Japanese reservoirs. Several simulation models for the prediction of turbidity are briefly reviewed. Finally, we propose a formula for optimum withdrawal for the effective drainage of turbid water from a stratified reservoir.
257 研究論文(学術雑誌)
共著
複合因擾乱が作用する水温成層場の乱流構造
室田明・阪口進一
水理講演会論文集

31, 497-502
1987/02



水面での熱的作用に加えて風応力や流動等による力学的擾乱が作用する停滞成層水域を対象とし, 乱流構造と鉛直混合過程との関連について論ずる。具体的には熱対流と振動格子が誘起する水温二層系内の「複合図擾乱」場を一方程式乱流モデルによって再現し,乱れエネルギー収支・水質輸送量等を解析する。乱流構造が把握されれば, 実験システムにおいてこれまでに得られた基礎的情報が汎用化され, 実際現象への応用も可能になると考える。
258 研究論文(学術雑誌)
共著
機械的擾乱と熱的擾乱が複合的に作用する水温成層場での内部変動特性に関する研究
室田明
土木学会論文集

375/ II-6, 171-179
1986/11



An experimental work is performed to examine the characteristics of internal fluctuations in two-layer thermal strata induced by the combined action of grid-oscillation and heating from below. The interfacial layer depth and the vertical deformation of interface are expressed as a function of Peclet number and the overall Richardson number which are defined from the grid-turbulence scaling velocity. 8ased on these results, it is found that the relative intensity of temperature fluctuation at the thermocline is proportional to Peclet number as well as to the inverse of Richardson number. It is concluded that the mechanical turbulence plays more predominant roles on the internal fluctuations than the thermal convection. However, the thermal stirring effectively contributes to the mixing process because of its buoyancy flux effects.
259 研究論文(国際会議プロシーディングス)
共著
Vertical Mixing Process in Thermally Stratified System Induced by Combined Action of Mechanical and Thermal Stirring
Murota,A.
Proc.APD-IAHR Congress

5, 183-202
1986/08



A model experiment is performed to examine the vertical mixing process due to the combined action of wind stress and thermal convection on the surface of thermally stratified water body. The stress-driven mechanical turbulence and thermally induced convective motion are simulated by means of an oscillating grid and a bottom plate heater, respectively. Introducing the characteristic scale of velocity defined by linearly superimposing the energy flux of mechanical turbulence and thermal convective motions, the mixing rate can be expressed as a unique function of an overall Richardson number. Based on the experimental law for mixing rate, we deduce an analytical solution for the time-dependent behavior of density field. Satisfactory agreement between the theory and the experiment is obtained.
260 研究論文(学術雑誌)
共著
機械的擾乱と熱的擾乱が複合的に作用する水温成層場での鉛直混合量に関する研究
室田明
土木学会論文集

369/ II-5, 61-70
1986/05



Model experiments are performed to examine the vertical mixing process in the case when the wind stress and thermal convection simultaneously act on the surface of thermally stratified water body. The stress-driven mechanical turbulence and thermally induced convective motions are simulated by means of the oscillating grid and the bottom plate heater, respectively. Using the characteristic velocity scale defined by linearly superimposing the energy flux of mechanical turbulence and thermal convection, the mixing rate can be expressed as a function of an overall Richardson number Analytical solutions for the mixing layer depth, specific density anomaly, etc. are derived based on the experimental law of mixing rate. Satisfactory agreement between the theory and experiments is obtained. Additionally, the regimes where the mechanical or thermal stirring effects dominate the mixing process, respectively, are systematically classified.
261 研究論文(学術雑誌)
共著
積分成層模型による貯水池水温構造の解析に関する研究
室田明
土木学会論文集

369/ II-5, 119-128
1986/05



An integral (bulk) layer model is devised for the prediction of thermal fields in reservoirs. The vertical mixing process is described by using the integral equation approach of a bulk mixed layer mode l. The horizontal advective process is evaluated by our developed theory for withdrawal f10w fields. Intending to obtain useful information on internal behaviors, a year-long field survey was carried out at a reservoir. It is demonstrated by the comparison between predicted data and observed data that the present analysis is capable of reproducing field measurements of water temperature with remarkable accuracy, regardless of its simple modeling. Applying the analysis, the non-dimensional hydraulic parameters which govern the thermal fields are derived which enables the c1assification of the types of stratification in reservoirs.
262 研究論文(学術雑誌)
共著
Analysis of Selective Withdrawal from Three-Layered Stratified System and Its Practical Application
Murota,A.
J.Hydroscience and Hydraulic Engineering

4/ 1, 31-50
1986/04



A density stratification with two distinct pycnoclines is generally produced in large reservoirs by the combined actions of surface heat exchange and substantial through-flows, or by the inflowing of suspended materials into the reservoir. An experimental and theoretical investigation for a three-layer system having two distinct interfaces is undertaken here to gain insight into the characteristics of withdrawal flow fields in such practical systems. First, the flow pattern and withdrawal characteristics in a two-layer system are examined. Second, extending the work on the two-layer system to the case of three-layer one, we devise an analytical method for evaluating the withdrawal ratio in each layer. The proposed analysis is also applied to two examples of practical problems in real reservoirs. One of them is the effective removal of turbid middle layer from a reservoir. Another application of this study concerns the introduction of the present analysis to our numerical model for the prediction of thermal fields in a reservoir. From these results, we find the present work to be highly useful in engineering aspects.
263 研究論文(学術雑誌)
共著
機械的擾乱と熱的擾乱が共存した密度成層場での鉛直混合に関する研究(その2)
室田明
水理講演会論文集

30, 697-702
1986/02



海域・湖沼に発達する水温成層の盛衰は水面を介して供給される熱的・力学的エネルギーの相互作用に支配される。著者等は性質の異なるこれら二種の擾乱エネルギーが水温成層場へ複合的に作用して誘起される場合の鉛直混合過程を解明するためこれまで基礎的実験を行なってきた。前報においては擾乱の速度・長さに関する代表量を用いて複合図擾乱によりもたらされた混合量の規準化を図り混合員IJを確立した。これにより混合率は複合因擾乱の代表特性量で定義されたリチヤードソン数の一価関数として表示された。本報においては,混合則に基づき別途得られた解析解を用いて混合過程を記述し混合則の妥当性を確認するとともに現象を支配する各水理量を導出してその物理的意義を明確にする。次に場のポテンシャルエネルギーの推移を評価することによって力学系と熱学系相互のエネルギー授受関係を定量的に示し,エネルギー推移過程を体系化する.実験は前回と同様,鉛直一次元アクリル水槽を用いて行なわれ,安定な水温二成層を底面に設置した振動格子と加熱底板によって混合させるという方式をとる。
264 研究論文(国際会議プロシーディングス)
共著
Field Observation and Numerical Modeling of Thermal Structure in a Pumped Storage ReservoirStirring
Murota,A.
Proc. IAHR Congress

21, 335-340
1985/08



To examine the contribution of external thermal and dynamic energies, such as surface wind stress, thermal convection and inflow and outflow discharges, to the destratification process in reservoirs, the authors carried out a year-long field survey of temperature fields at the upper reservoir of a pumped storage plant. The field data provides insight into the effects of meteorological and hydrological factors on the formation and deformation of thermal strata. The reservoir undergoes two distinct thermal cycles: (1) During the heating period, i.e., spring to summer, the advective process, resulting from successive pumped storage operation, predominantly effects the thermal structure. (2) During the cooling season, i.e., fall through winter, the discharge-to-volume ratio is radically reduced by the absence of the turbine operation; thus thermal convection gains relative importance in the thermocline descending process. By the action of pumping and power generation, as well as by the surface heat-exchange process, distinct thermoclines develop and thus the temperature field presents a typical layer structure. Based on the field data, we develop a mathematical model for the prediction of the temperature fields in reservoirs. The model is formed paying attention on the mechanically and thermally induced vertical mixing process. It is demonstrated that, despite the simplicity of the model, the present analysis is capable of accurately reproducing field measurement of thermal structure. We wish to emphasize that the model predicts the thermocline descending and the resulting turnover process which have never been successfully predicted by any previous models.
265 研究論文(学術雑誌)
共著
三成層密度場の取水流動に関する研究
室田明
土木学会論文集

357/ II-3, 105-113
1985/05



In pumped storage reservoirs, a well mixed layer is often produced between the upper and lower pycnoclines by discharges from and into the reservoirs. A turbid middle layer may develop when the flood flows into the thermally stratified reservoirs. To understand the flow fields of such systems, the withdrawal from the three layered stratified systems is investigated. A theoretical analysis is performed to estimate the incipient withdrawal and the discharge in each layer. The validity of the analysis is confirmed by laboratory experiments. By using the theory, the optimum height of the outlet for the drainage of the turbid middle layer fluid is evaluated, in practical sense, which may enable the effective operation of the selective withdrawal arrangement to reduce the retardation of turbidity.
266 研究論文(学術雑誌)
共著
機械的擾乱と熱的擾乱が共存した密度成層場での鉛直混合に関する研究
室田明
水理講演会論文集

29, 407-412
1985/02



陸水域・海水域の表層では風の応力と熱の出入りが水表面へ複合的に作用し、内部の水温構造と水質挙動に大きく影響する。このような水温成層場における鉛直混合過程に関し、これまでは外因が風応力のような機械的擾乱かあるいは熱対流のような熱的擾説かのいずれかを対象とした場合に限り研究が行なわれてきた.前者に関しては振動格子や種々の単純化されたせん断流による実験モデル化がなされている。後者に関しては密度成層場の上方からの冷却、下方からの加熱、あるいは浮力流体の供給等の形態でモデル化されている。しかし、現実には冒頭に記したように二種の擾乱が複合的に作用して鉛直混合現象が生じており、各々の外因による混合量と各外力が接合した場合の混合量との相互関係を明らかにする必要がある。そこで、本研究では二種の外力が負荷された場を想定して、機械的擾乱と熱的擾乱が同時に作用する密度成層場での混合過程に関する実験モデル化を行ない、混合量の定量判面を試みた。単一外力を対象とした既往の実験結果との連結を意図して、本実験での各擾乱の発生法は広く一般的に使われている方法を採択する。すなわち、機械的擾乱は振動格子を用いて発生させる。熱的擾乱は底面を加熱することによって発生させる。また密度場としては安定な水温二成層場を対象とする。
267 研究論文(学術雑誌)
共著
混合層模型による貯水池水温構造の予測
室田明
水理講演会論文集

29, 395-400
1985/02



貯水池水温構造の代表特性量(例えば躍層の存在期間や成層強度)を気象・水文条件や貯水池の幾何形状の関数として表現することは水工学上有用である。その際極力簡便な手順で入力条件より水温構造を評価することが肝要となる。しかし、MITモデルに端を発し、それを基盤とした種々の予測手法は水温分布形の精確な予測に主眼がおかれたシミュレーションモデルであり計算の繁雑性の故、上記の目的には適さない。しかもこれらには任意の未定定数を多く含む点、鉛富混合過程のルーチンが直接的には組み込まれていない点等の問題も指摘されている。例えば躍層の寿命を把握するためには鉛直混合量を正確に表現する必要があることは言うまでもない。本研究では冒頭記した目的にかなうよう貯水池水温構造を単純化し鉛直混合を考慮したモデル化を行なって簡便な水温予測手法を確立することに重点をおく。また本報告で示す水温予担拡が移流効果の大きい場合と鉛直混合効果の大きい場合の双方においてともに有効であることを確認するために、交換率が人工的に大きく季節変動する純揚水式発電用上部貯水池を対象として水温観測を行なった。本報告の前半では水温観測結果の概要を述べ、後半においてモデルの定式化と解析結果を示す。解析値と予測値との此鮫より本予測怯の有用性が検証された。特にこれまでの予測手法において用いられている対流混合の表現によっては評価できないような循環期の躍層低下過程が精度良く表現された。
268 研究論文(学術雑誌)
共著
複合閉鎖水域における内部界面セーシュに関する研究
室田明
土木学会論文集

351/ II-2, 243-246
1984/11



The thermocline oscillation observed in the stratified water mass, such as, deep lakes, reservoirs and land-locked bays, are sometimes generated by the resurging effects after the stop of the wind set-up motion. The oscillation characteristics of the density interface become much complex in the case of complicated geometry, e.g. reservoirs with several branches, bays composed of many inlets, etc. The authors developed the theory for the, interfacial seiche motion in the two layered and multi composed water mass by applying the theory of the surface seiche. Additionally, a laboratory experiment was performed by using the model tank composed of four channel elements with rectangular cross sections. Satisfactory agreements between the theory and experiment were obtained.
269 研究論文(学術雑誌)
共著
二成層場および連続成層場における熱塩対流に関する研究
室田明
土木学会論文集

345/ II-1, 73-82
1984/05



In order to study the mass transport process produced by the thermal convection, the thermosolutal convection in the two-layered and continuously stratified systems composed of heat-salt complex is investigated, experimentally and theoretically. Our preceding results, i.e., the stability criterion for the system with arbitrary distribution profiles of two density components and the evaluation of the diffusive and convective components of the heat-salt flux across the density interface, are introduced to develop the numerical model for the mixing process. The numerical results agrees well with the experimental data. In addition, the transforming process on the internal energy into the potential energy through the vertical mixing is quantitatively understood.
270 研究論文(大学,研究機関紀要)
共著
Effects of Surface Heat Exchange and Bottom Geometry on Thermal Structure of Water Body
Murota,A.
Technol.Repts. Osaka Univ.

34/ 1753, 101-109
1984/03



Dynamic process of the thermal structure of water body produced by the heating or cooling at the water surface is investigated. Two types of experiments are carried out. First, a fundamental experiment using the one-dimensional container is performed in order to relate the vertical mixing rate with the velocity and space scales of the thermal convection. The functional relationship between the normalized deepening rate of the thermocline and Richardson number is theoretically derived. It is found that the proposed functional relationship can universally express all experimental results. Secondly, the heat transport process in the twodimensional container with a step-like bottom shape is examined experimentally. The non-dimensional horizontal heat flux can be expressed as a function of the ratio of the shallow water depth to the deep water depth. The result suggests that the bottom geometry of the closed water mass, such as lakes and reservoirs, may have significant effects on the heat transport process.
271 研究論文(学術雑誌)
共著
Stability and Vertical Mixing Process in Double-Diffusive Stratification System Composed of Heat-Salt Complex
Murota,A.
J.Hydroscience and Hydraulic Engineering

1/ 1, 53-63
1983/04



The stability and the vertical mixing process in an double-diffusive stratification system composed of heat-salt complex in which a stable gradient of salt concentration is heated at the bottom of the container are investigated, experimentally and theoretically. Using the variational principle, a stability analysis for the system with arbitrary distribution profiles of two density components is presented. The theoretical solutions are applicable to any possible distribution profiles of two components. Applying the theory to the system with heat-salt complex, we have satisfactory agreement between the theoretical and experimental results. At the initial stage of the instability, a sharp interface of stratification is formed at a finite depth below which the fluid is uniformly mixed. To simply discuss the convection process at the double-diffusive interface, an experiment in which a fresh-salt two-layer system is heated at the bottom of the container is conducted. As the density interface becomes unstable due to the negative thermal buoyancy, the interfacial fluctuations are generated and turbulent lumps of buoyant fluid are increasingly entrained across the interface. This means that both heat and solute flux is composed of both the advective entrainment and the molecular diffusion. These two types of transportation are confirmed quantitatively by evaluating individually the conductive and convective components of the heat flux across the interface. The interfacial fluctuations observed in this experiment have some similar characteristics to those of the Linden ’s experiment of the vortex ring (4). Finally, it is verified that the entrainment coefficient and Richardson number has the well-known power law which is reported by some researchers in the experiments of the deepening process induced by the mechanical energy.
272 研究論文(大学,研究機関紀要)
共著
Effects of Temperature and Salinity Profiles on Stability Criterion in Double-Diffusive Stratification
Murota,A.
Technol.Repts. Osaka Univ.

33/ 1698, 115-123
1983/03



The stability of a double-diffusive stratification system is investigated. A stability analysis for the system with arbitrary profiles of two density components is developed using the variational principle. The theoretical solutions are very useful because they can be applied to every possible profile of two components. Applying the theory to the heat-salt system, the thickness of the convective layer at the marginal stability and the critical condition can be reasonably evaluated. The theoretical results are in good agreement with the laboratory experimental ones. As a result, it is concluded that the effect of the profiles of the density components should be taken into consideration when we examine the stability of a double-diffusive stratification system.
273 研究論文(学術雑誌)
共著
熱塩成層の安定性および界面混合現象について
室田明
水理講演会論文集

27, 165-170
1983/02



湖沼・貯水池といった停滞水域の温度成層場においては風・流出入等の機械的擾乱とともに水表面熱収支にともなう熱対流擾乱が鉛直方向の水質交換を促進させる重要念要因である。機械的擾乱に関してはとれまで各種形態の成層せん断流や撹乱格子といった実験モデルによって連行機構に関する研究成果が積み重ねられているのに対し熱的擾乱がもたらす成層の鉛直混合機構については未だ不明な点が数多い。本研究では水質輸送と熱的擾乱が複合するケースとして熱塩成層場の問題を取り挙げその安定性と連行プロセスに対する検討を行なう。
274 研究論文(大学,研究機関紀要)
共著
Stability and Vertical Mixing of a Two-Layer Density Stratification Heated at the Bottom
Murota,A.
Technol.Repts. Osaka Univ.

32/ 1698, 115-123
1982/10



Vertical mixing process of two-layer salinity stratification due to heating at the bottom is investigated by a laboratory experiment. As the density interface becomes unstable due to the negative thermal buoyancy, turbulent patches of buoyant fluid are entrained increasingly across the interface. This means that both heat and solute fluxes are composed of the advective entrainment in addition to the molecular diffusion. It is confirmed quantitatively from the relation between the thermal flux and the interfacial fluctuation. Furthermore, in order to predict the time history of the mixing process, a numerical model is developed using the experimental results.
275 研究論文(学術雑誌)
共著
Diffusive Regimeにおける密度成層の鉛直混合に関する研究
室田明
水理講演会論文集

26, 555-561
1982/02



熱対流がもたらす物質輸送機構を解明するために底面加熱された塩分成層の鉛直混合現象に関する研究を行なった。安定な連続密度成層を底面から加熱した場合、準一様密度の対流層と密度界面から成る多段階成層が形成される。本研究では密度界面を通過する熱量・塩分のフラックスが分子拡散によるものばかりでなく、大規模な水塊の取りとみによる移流的物質輸送が存在しそれが極めて重要である点に着目して実験および解析を行なった。まず熱対流と移流的物質輸送量との関係を考慮して対流層での物質保存則を誘導した。つぎにこれらを多段階密度成層に応用し任意の分布形を有する連続成層から対流構造が発達する過程のモデル化をおこなった。その結果、対流層厚の増減・層の融合現象さらに貯水池濁水層のごとく変曲点を有するような分布形での対流層の発達特性などこれまで明らかにされなかった現象を表現することが可能となった。模型実験は、(i)塩淡二成層の底面加熱実験、(ii)連続密度成層の底面加熱実験の二種類を行ない解析モデルとの整合性を吟味し良い一致を得た。とくに複数界面に対しても連行による層体積の変化を考慮すれば界面位置の移動特性を巧みに表現できることを示した。
276 研究論文(大学,研究機関紀要)
共著
Breaking of Internal Gravity Wave on Slope
Murota,A., Hirata,T.
Technol.Repts. Osaka Univ.

30/ 1543, 255-261
1980/10



Laboratory experiments on an internal wave breaking on a slope have been performed to clarify a mixing mechanism of a water quality in a two-layered system. In a breaking zone, an eminent forward current is generated near the bottom. The forward particle velocity develops to exceed a phase speed of the internal wave and break the internal wave with only one large vortex formation in combination with striking reflux near the interface. The large vortex rolls a little diluted fluid into a heavier layer and has a predominant role in the mixing layer formation and the density stratification in the breaking zone. In this paper, first, the criterion of the internal wave breaking on the slope is established. Secondly, the mixing mechanism of the water quality is discussed from the visualized images and the density variations.
277 研究論文(学術雑誌)
共著
内部重力波の基本特性と斜面上における砕波現象について
室田明・平田健正
土木学会論文報告集

301, 61-70
1980/09




278 研究論文(学術雑誌)
共著
斜面上における内部重力波の砕波について
室田明・平田健正
水理講演会論文集

23, 375-380
1979/02



塩淡ニ層界面に内部重力波を生起させ,可視化手法により内部重力波の浅水変形から砕波変形に至る過程を定性的に明らかにする.そして,より現実に則した密度モデルを用いて,斜面上における内部重力波の砕波機憾の究明を目的とする.