1988 Fiscal Year Final Research Report Summary
Study on Deformation Process of Sand Bars at River Mouth
| Project/Area Number |
62460160
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Hydraulic engineering
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| Research Institution | Kanazawa University |
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Principal Investigator |
KITAURA Masaru Kanazawa University, Faculty of Technology, Professor, 工学部, 教授 (70026269)
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| Co-Investigator(Kenkyū-buntansha) |
MIYAJIMA Masakatsu Kanazawa University, Faculty of Technology, Research Associate, 工学部, 助手 (70143881)
UJIBASHI Yasuyuki Kanazawa University, Faculty of Technology, Research Associate, 工学部, 助手 (60092764)
TSUJIMOTO Tetsuro Kanazawa University, Faculty of Technology, Associate Professor, 工学部, 助教授 (20115885)
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| Project Period (FY) |
1987 – 1988
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| Keywords | Sand Bars at River Mouth / Sediment Transport / Sea Wave / Sediment Transport Formula / Relaxation Process / 非平衡流砂 / 緩和過程 / 側岸侵食 |
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| Research Abstract |
At river mouth, sand bar is often formed due to interaction of sediment transport by river flow and that by waves, and it affects the flow capacity of the river severely. Hence, an appropiate modelling of deformation process of sand bar at river mouth is required from the view point of river engineering.
As for sediment transport in rivers, effect of unsteadiness and non-uniformity of flow on sediment transport is in particular interesting, and thus a non-eguilibrium transport law has been established to describe transient process of sediment transport under such unsteady nonuniform conditions.
Sediment transport by weves is more complicated, but somewhat simplified modelling is required for modelling variation process of river morphology at river mouth. Based on laboratory studies, Ursell number is used to predict the direction of sediment transport, and transport discharge formula using Shields number has been proposed, which is quite similar to that established in river region. In order to evaluate the relation between Shields parameter and the characteristics of waves, applicability of a linear filter method is tested.
A relaxation model is proposed to descride deformation process of sand bars at river mouth totally, in which equilibrium section of river mouth is used as a parameter instead of complicated parameters related to transport capacity of flow and waves. Based on the field data of actual rivers, the applicability of the present analytical model for deformation process of sand hars has been inspected.
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