2001 Fiscal Year Final Research Report Summary
Study on quasi three-dimensional numerical model for nonlinear random waves.
| Project/Area Number |
10450180
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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 | University of Tokyo |
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Principal Investigator |
ISOBE Masahiko Department of Environmental Studies, Univ. of Tokyo, Professor, 大学院・新領域創成科学研究科, 教授 (20114374)
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| Co-Investigator(Kenkyū-buntansha) |
SASAKI Jun Department of Environmental Studies, Univ. of Tokyo, Associate Professor, 大学院・新領域創成科学研究科, 助教授 (50292884)
SATO Shinji Department of Civil Engineering, Univ. of Tokyo, Professor, 大学院・工学系研究科, 教授 (90170753)
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| Project Period (FY) |
1998 – 2000
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| Keywords | short-crested random waves / nonlinear waves / breaking waves / short-crested random wave basin / numerical model / swash zone / nonlinear mild-slope equations |
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| Research Abstract |
In this study, a numerical model of nonlinear, random wave transformation in the vertical two dimensions is developed first. The basic equations of the model are the nonlinear mild-slope equations proposed by Isobe (1994), and an efficient numerical algorithm is developed in addition to the boundary condition at the wave generator which can generate long waves as well. A moving boundary is installed to deal with the wave motion in the surf zone. By integrating these factors, a numerical model is proposed to predict the profile, velocity and turbulence of random waves on a general topography from deep to shallow water. A two dimensional experiment is performed to develop and verify the numerical model by measuring the wave field including the swash zone.
Next, the breaking criteria of short-crested random waves is studied to incorporate with a three dimensional numerical model for random waves. A short-crested random wave basin is developed to reproduce short-crested random wave fields. The wave generator is more sophisticated than existing ones, with a stable feed back system to absorb reflected waves. Data for the breaking criteria are obtained by experiments by this wave basin.
To develop a quasi-three dimensional numerical model of nonlinear random waves, numerical models of wave transformation are developed based on the nonlinear mild-slope equations and Boussinesq equations. These models are verified by applying to the wave diffraction and run-up problems. By combining the Boussinesq equations model with a model to predict the vertical velocity distribution due to undertow, a quasi-three dimensional numerical model of nonlinear random waves is developed.
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