Study on quasi three-dimensional numerical model for nonlinear random waves.

非线性随机波准三维数值模型研究。

基本信息

批准号：
10450180
负责人：
ISOBE Masahiko
金额：
$ 4.03万
依托单位：
University of Tokyo
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 2000
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-10450180/
关键词：
short-crested random waves nonlinear waves breaking waves short-crested random wave basin numerical model swash zone nonlinear mild-slope equations 非線形性海浜流多方向不規則造波装置鉛直断面分布戻り流れ水槽実験

项目摘要

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.

在这项研究中，首先开发了垂直二维非线性随机波变换的数值模型。模型的基本方程是Isobe(1994)提出的非线性缓坡方程，除了波发生器的边界条件外，还开发了一种有效的数值算法，可以产生长波。安装移动边界来处理冲浪区的波浪运动。通过整合这些因素，提出了一个数值模型来预测从深水到浅水的一般地形上随机波的轮廓、速度和湍流。通过测量包括斜流区在内的波场，进行了二维实验来开发和验证数值模型。接下来，研究了短峰随机波的破坏准则，并将其与随机波的三维数值模型结合起来。开发了短峰随机波盆来再现短峰随机波场。该波发生器比现有的波发生器更复杂，具有稳定的反馈系统来吸收反射波。为了建立非线性随机波的准三维数值模型，基于非线性缓坡方程和Boussinesq方程建立了波浪变换的数值模型。这些模型通过应用于波衍射和助跑问题得到验证。通过将 Boussinesq 方程模型与预测底流引起的垂直速度分布的模型相结合，建立了非线性随机波的准三维数值模型。