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Study on Numerical Models of Nearshore Currents Including Wave Nonlinearity or Wave Irregularity

包含波浪非线性或波浪不规则性的近岸流数值模型研究

基本信息

批准号：
01550408
负责人：
YAMAGUCHI Masataka
金额：
$ 1.41万
依托单位：
Ehime University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1989
资助国家：
日本
起止时间：
1989 至 1990
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-01550408/
关键词：
Finite amplitude waves Irregular waves Nonlinear long waves Wave transformation model Nearshore current model Characteristic method Finite difference model 非線形長波

项目摘要

The conclusions of this study are as follows ;(1) Mathematical proof is given that the interrelation among the existing cnoidal wave theories is such that the Chapppelear theory includes the other theories.(2) Wave shoaling and refraction due to current-depth variations are analyzed with use of higher order solutions of Stokes and cnoidal waves.(3) Two models of wave transformation and nearshore currents in which wave characteristics are estimated with Stokes or cnoidal wave theory are established.(4) One-dimensional and two-dimensional models of wave transformation are developed on the basis of characteristics solution for nonlinear long wave equations. These models are also applicable to the computation of transformation of irregular waves.(5) A model for refraction computation of irregular waves due to time-varying currents and water depth is established on the basis of conservation of wave action spectral density. Numerical computation shows that time-dependency of currents gives rise to reduction in the amplification effect of directional spectrum due to opposing currents.(6) A model of nearshore currents induced by irregular waves in the presence of coastal structures is completed, in which the effect of diffraction and reflection are evaluated with approximate ways. The model reasonably explains the experimental data of wave transformation and the formation of curent patterns appropriate to their configuration of structures.

本研究的结论如下：(1)从数学上证明了现有的余弦波理论之间的相互关系，使得Chapppelear理论包含了其他理论。(2)利用Stokes和余弦波的高阶解，分析了由于海流深度变化引起的波浪浅滩和折射。(3)波浪变换和近岸海流的两种估计波浪特性的模型 (4)在非线性长波方程特征解的基础上建立了波动变换的一维和二维模型。这些模型也适用于不规则波变换的计算。(5)基于波浪作用谱密度守恒,建立了时变水流和水深引起的不规则波折射计算模型。数值计算表明，海流的时间依赖性会导致方向谱放大效应因反向海流而减弱。(6)完成了海岸结构存在下不规则波诱发的近岸海流模型，用近似方法评价了绕射和反射的影响。该模型合理地解释了波浪变换的实验数据以及与其结构配置相适应的电流模式的形成。