1997 Fiscal Year Final Research Report Summary
Study on swash zone flow field and foreshore deformation characterizing run-up front as a moving boundary
| Project/Area Number |
08650613
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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 | Kagoshima University |
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Principal Investigator |
ASANO Toshiyuki Kagoshima Univ., Faculty of Engrg., Associate Professor, 工学部, 助教授 (40111918)
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| Project Period (FY) |
1996 – 1997
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| Keywords | swash zone / run-up waves / sediment transport / beach scarp / percolation / moving boundary / beach deformation |
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| Research Abstract |
The purpose of this study is to investigate the swash zone dynamics including velocity field, sediment transport and foreshore deformation.
For the hydrodynamics in the swash zone, moving boundary treatment at a run-up front should be required to reproduce the swash zone velocity precisely. The investigator has been studying this subject for almost one decade, and already developed 2-dimensional wave model based on non-linear long-wave equation.But the study was mainly restricted for monochromatic waves. In this project, the analysis was expanded to irregular wave fields. Using a data-base of large-scale wave basin experiments conducted at the Central Electric Power Institute 1996, interaction mechanism between run-up waves and long period waves was examined. It is found that the time series data of run-up waves are not governed by the individual incoming waves but by the long wave component.
For the sedimentation mechanism in the swash zone, quantitative estimations on the sediment transport rate were conducted. Measurements on sand transport rate were done using florescent colored particles. In the foreshore zone, the characteristic topography known as a scarp is often generated. A numerical model to reproduce the swash zone morphology including the scarp was proposed. These analyzes revealed that modeling beach slope failure or avalanching mechanism is essential to reproduce the foreshore beach deformation. Seepage effects into the sand bed are also important to consider the net sediment transport rate in a swash zone. These subjects are remained for the future study.
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