2000 Fiscal Year Final Research Report Summary
Basic study of Design Method for the Main Channel of Meandering Compound Channels
| Project/Area Number |
10450183
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| Research Category |
Grant-in-Aid for Scientific Research (B).
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
水工水理学
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| Research Institution | Hiroshima University |
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Principal Investigator |
FUKUOKA Shoji Faculty of Engineering, Hiroshima University, Professor, 工学部, 教授 (30016472)
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| Co-Investigator(Kenkyū-buntansha) |
KUROKAWA Takeshi Faculty of Engineering, Hiroshima University, Research Associate, 工学部, 助手 (50325148)
WATANABE Akihide Faculty of Engineering, Hiroshima University, Associate Professor, 工学部, 助教授 (00240474)
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| Project Period (FY) |
1998 – 2000
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| Keywords | Compound meandering channel / Clnsteadiness of Flood flow / Storage volume in a river / Planform / Numerical analysis / Accuracy of discharge measurement |
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| Research Abstract |
(1) Comparing stage hydrographs for meandering compound channel and meandering single channel it was observed that, compound meandering channel had early response giving high values during rising stage and delayed response giving high values during falling stage. Also for both compound meandering channel and meandering single channel, increase of sinuosity and unsteadiness brings faster occurrence of the maximum velocity and the large increase rate of the depth in the rising stage.
(2) A quantitative estimation of the flood flow storage and attenuation of the peak discharge in channels was investigated. Laboratory experiments in a compound meandering channel were performed and observed flood data from Otagawa river were analyzed. Results of comparison of the experimental data and Otagawa river data indicated similar characteristics of flood flow storage.
(3) A comparison between experimental results and a 2 -dimensional unsteady flow numerical model simulations is made for flood propagation in a compound meandering channel. The model is based on a finite volume discretization on a staggered gird with upwind scheme in flux is presented, it handles drying and wetting process for a flood plain, complex geometry and discontinuities, which are the main requirements for modeling compound channel flows. The existing knowledge on flood flow phenomenon in compound channels is advanced through comparative studies of unsteady flow experiments and numerical simulations. Comparison between measured date and model simulations show generally good agreement.
(4) Since most of the rivers in Japan are compound meandering channels, which have complex flow field, we check the accuracy of discharge measurements of those compound channels. The accuracy of discharge measurements is investigated in a compound meandering channel by using a there dimensional numerical analysis. The discharge measurement is clarified from the Eulerian and the Lagrangian methods.
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