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

在这项研究中，首先建立了垂直二维非线性随机波变换的数值模型。该模型的基本方程是Isobe(1994)提出的非线性缓坡方程，除了波浪发生器的边界条件外，还发展了一种有效的数值算法。设置了一个移动边界来处理冲浪区内的波浪运动。通过综合这些因素，建立了一个数值模型来预报从深水到浅水的一般地形上的随机波的剖面、速度和湍流。进行了二维实验，通过测量包含斜坡区的波浪场对数值模型进行了发展和验证。其次，研究了短峰随机波的破碎准则，并将其与三维随机波数值模型相结合。为了再现短峰随机波场，开发了一个短峰随机波池。该造波机比现有的造波机更复杂，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浪的准三维数值模型，基于非线性缓坡方程和Boussinesq方程，建立了波浪变形的数值模型。将这些模型应用于波浪绕射和爬升问题，得到了验证。将Boussinesq方程模型与底流垂向速度分布预报模型相结合，建立了非线性随机波的准三维数值模型。

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.