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.

在目前的研究中，发现倾斜海滩上的非线性破碎波导致海水渗入海床。流动可视化显示，水在上升点附近沿径向移动到海床，然后在破裂点附近返回到海面。海床表面压力的测量揭示了渗滤水与渗透水之间的关系。流量和海床表面的时间平均压力。发现基于非线性水波理论的时间平均压力可以通过波浪建立和下降来估计。假设达西定律计算了海底压力分布。边界上的压力来自波浪设置和设置。采用有限差分法求解时均压力的拉普拉斯方程。计算的速度分布与观测到的流型一致。最后，通过数值模拟明确了海滩坡度与冲浪区渗流之间的关系。冲浪区内部流动与泥沙的冲刷密切相关。的生物活性。因为海水是通过渗入海床而被净化的，流入海床的水正在向冲浪区的底栖生物输送一种营养物质和氧气。目前的研究揭示了波浪与沿海生态系统之间的关系。