| Project/Area Number |
08455227
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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 | THE UNIVERSITY OF TOKYO |
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Principal Investigator |
ISOBE Masahiko Univ.of Tokyo, Dept.of Civil Eng, Professor, 大学院工学系研究科, 教授 (20114374)
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| Co-Investigator(Kenkyū-buntansha) |
SASAKI Jun Univ.of Tokyo, Dept.of Civil Eng., Research Associate, 大学院工学系研究科, 助手 (50292884)
YU Xiping Univ.of Tokyo, Dept.of Civil Eng., Associate Professor, 大学院工学系研究科, 助教授 (90253632)
横木 裕宗 茨城大学, 工学部・都市システム工学科, 講師 (70240190)
ディバジニア モハンマド 東京大学, 大学院・工学系研究科, 助教授 (80260503)
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| Project Period (FY) |
1996 – 1997
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| Project Status |
Completed (Fiscal Year 1997)
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| Budget Amount *help |
¥6,300,000 (Direct Cost: ¥6,300,000)
Fiscal Year 1997: ¥2,900,000 (Direct Cost: ¥2,900,000)
Fiscal Year 1996: ¥3,400,000 (Direct Cost: ¥3,400,000)
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| Keywords | Coast / Swash zone / Sedimentation / Longshore sediment transport / Wave |
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| Research Abstract |
Swash zone dynamics is an important factor in computing longshore sediment transport rate. In the present study, a numerical model is developed to predict the onshore distribution of the longshore sediment transport rate by taking into account the moving shoreline boundary condition.
Boussinesq-type equations were adopted as the governing equations that include non-linearity and dispersivity, and a breaking model was incorporated. The longshore coordinate and the time were combined into one independent variable under the assumption of a uniform water depth in the longshore direction. The offshore boundary condition included the radiation boundary condition which can absorb the outgoing waves ; the onshore boundary condition was developed to reproduce the moving shoreline in the swash zone.
We applied this model to the numerical computations with obliquely incident waves to simulate wave kinetics including swash motion, and found that the model can reproduce the moving shoreline as well as wave deformation and breaking correctly.
In addition to the wave field, the nearshore current field was modeled by considering the bottom friction. By incorporating the sediment transport formula proposed by Dibajnia and Watanabe (1994), the model resulted in a bi-modal distribution, with one peak around the breaking point and the other around the shoreline, which has been recognized in the laboratory experiment.
As a result, a general numerical model for obliquely incident waves on the bottom topography of straight and parallel offshore contours is developed, which can reproduce non-linear wave deformation, swash motion, longshore current, and onshore distribution of the longshore sediment transport rate
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