1999 Fiscal Year Final Research Report Summary
Research on Free Meandering and Channel Width Formation in Channels with Mixture Grain Size Bed Material
| Project/Area Number |
10650497
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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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 | HOKKAIDO UNIVERSITY |
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Principal Investigator |
SHIMIZU Yasuyuki Hokkaido Univ., Graduate School of Eng., Associate Professor, 大学院・工学研究科, 助教授 (20261331)
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| Co-Investigator(Kenkyū-buntansha) |
BABA Hitoshi Hokkaido Development Bureau, Civil Engineering, 開発土木研究所・河川研究室, 室長(研究職)
IZUMI Norihiro Hokkaido Univ., Graduate School of Eng., Assocate Professor, 大学院・工学研究科, 助教授 (10260530)
SEKINE Masato Waseda University, Dept. of Engineering, Associate Professor, 理工学部, 助教授 (60187854)
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| Project Period (FY) |
1998 – 1999
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| Keywords | Mixture Grain / Fine Sand / Washload / Suspended Load / Channel Width / Flood Observation / Secandary Flow / Numerical Model |
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| Research Abstract |
Fine sand deposition on a floodplain during the Abukuma River flood in 1998 is studied both observationally and theoretically. It is found from the observation that most of the deposition consists of fine sand of about 0.1 mm in diameter, which is commonly refer to washload that is not included in bed material. The observed data shows that the deposition is maximized around 10 m inside of the floodplain along the boundary between the main channel and the floodplain. This phenomenon is found to be well-explained by the theory of suspended sediment transport. The predicted value of the magnitude of the deposition agrees well with the observed value with the use of suspended sediment concentration obtained in another observation.
A numerical model is proposed to investigate free meandering of river. Flow field, bed deformation, bank erosion and channel migration are calculated numerically with a general non-orthogonal coordinate system which can be applied to moving boundary conditions. Flow field is calculated from two dimensional momentum equations and continuity equation. Bed deformation is calculated from continuity equation of bed load transport. Bank erosion and deposition is estimated from critical slope of bank material and emergence of bed due to the bed deposition. Time dependent change of channel geometry is calculated with an iteration process of these procedures. Calculated results are favorably compared with experimental results with movable bed and bank, and thus the accuracy of new model is verified.
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Research Products
(12 results)
