Hydrodynamic analysis of nonlinear waves for assessment of coastal ecosystems

用于评估沿海生态系统的非线性波浪水动力分析

基本信息

批准号：
10450385
负责人：
MORI Kazu-hiro
金额：
$ 5.76万
依托单位：
Hiroshima University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 1999
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10450385/
关键词：
Costal ecosystems environmental conservation nonlinear waves seawater percolation

项目摘要

In the present research, it was found that nonlinear breaking waves on a sloping beach caused sea water percolation into sea bed. The flow visualization showed that the water moved into the sea bed with radial direction neat the run-up point, and then returned to the surface near the breaking point.Measurement of the pressure on the surface of sea bed revealed the relation between the percolating water flow and the time averaged pressure on the surface of sea bed. The time averaged pressure was found to be estimated through the Wave Set-up and Set-down based on the nonlinear water wave theory.The pressure distribution in the sea bed was calculated assuming Darcy's law. The pressure on the boundary was derived from Wave Set-up and Set-down. Laplace equation for the time-averaged pressure was solved by finite difference method. The calculated velocity distribution was in accordance with the observed flow pattern.Finally, the relation between the slope of beach and percolation in the surf zone was made clear through the numerical simulation.Internal flow inside the surf zone closely relates to the purging of silt and the biological activities. Because the sea water is cleaned up by percolation into sea bed and water flow into sea bed is transporting a kind of nutrients and oxygen to benthos in the surf zone. The present research threw light on the relation between waves and costal ecosystems.

在本研究中，发现在倾斜海滩上的非线性破裂波浪导致海水渗透到海床中。流动可视化表明，水在径向上移动到海床中，整洁了升级点，然后返回到断裂点附近的表面。海床表面压力的测量显示出渗透水流与海床表面上的时间平均压力之间的关系。发现平均压力的时间是通过波浪设置估算的，并根据非线性水浪理论进行估算。假设达西定律，计算了海床的压力分布。边界上的压力源自波浪设置和固定。通过有限的差异方法求解了时间平均压力的拉普拉斯方程。计算出的速度分布与观察到的流动模式一致。在最后，通过数值模拟，清除了海滩斜率与冲浪区渗透之间的关系。在冲浪区内的内部流与净化硅的净化密切相关。因为海水通过渗透到海床上清理，并且水流流入海床，将一种营养物质和氧气运输到冲浪区的底栖生物中。本研究阐明了波浪与沿海生态系统之间的关系。