2022 Fiscal Year Final Research Report
Development of bed variation analysis method considering two-phase non-equilibrium motions of flow and sediment
Project/Area Number |
19K15102
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Research Category |
Grant-in-Aid for Early-Career Scientists
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Allocation Type | Multi-year Fund |
Review Section |
Basic Section 22040:Hydroengineering-related
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Research Institution | Chuo University |
Principal Investigator |
Gotoh Takahisa 中央大学, 研究開発機構, 機構准教授 (70634682)
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Project Period (FY) |
2019-04-01 – 2023-03-31
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Keywords | 掃流砂 / 浮遊砂 / 河床変動解析 / 準三次元解析 / 非平衡流砂モデル |
Outline of Final Research Achievements |
In this study, we developed a new riverbed deformation analysis method that considers the non-equilibrium motion of bed load and suspended sediment by treating flow and sediment movement as a two-phase flow. It was applied to the movable bed experiment with the bridge pier, and the scouring in front of and around the pier and the sedimentation behind the pier were explained. However, since actual rivers have mixed grain sizes, it is difficult to calculate the sediment motion equation for each grain size in consideration of the interaction with the flow. Therefore, the developed calculation model was simplified and applied to the August 1981 flood at the mouth of the Ishikari River, where suspended sediments were predominant. As a result, it was able to explain the three-dimensional flows, suspended sediment movements and bed variations due to compound meandering channel flows.
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Free Research Field |
水工学
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Academic Significance and Societal Importance of the Research Achievements |
本研究では,従来は掃流砂と浮遊砂を別個に評価していた河床変動解析法に対して,乱流場を考慮した粒子の運動方程式を解析することにより,乱れの作用により掃流砂から浮遊砂へ遷移する過程を評価し,掃流砂と浮遊砂の運動を一体的に扱う新しい河床変動解析法を開発している. これにより,細粒土砂の多い河川で克つ土砂移動の非平衡性の強い河口付近の河床変動や河床波の発達・変形,構造物周辺の河床変動等を,より力学的に忠実に流れと土砂移動現象を理解することが出来,今後の対策の検討にも応用できる.
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