基于分层Boussinesq类模型的孤立波爬坡模拟

Numerical Simulation of Solitary Wave Runup and Rundown on a Planar Beach Using a Layered Boussinesq-type Equation

波浪爬坡是自然界中普遍存在的现象,是近岸防波堤等结构物设计需要考虑的因素。本文采用分层Boussinesq类方程对近海岸波浪爬坡开展数值模拟研究,采用有限差分方法数值离散二层Boussinesq类方程,建立数值波浪模型。根据Synolakis 1986年的物理实验,数值模拟孤立波在梯形水道上的爬坡,验证了分层Boussinesq方程波浪模型在该研究中具有很好的适用性和较高的精度。模型较好地预报了波浪爬高的变化趋势。预报的波浪爬坡高度大于实验测量值,主要原因是实际的底摩擦大于模型中的底摩擦。

Wave runup and rundown is a ubiquitous phenomenon in the nature, which has to be taken into account in the design of offshore structures such as bulwark. Solitary wave runup and rundown is simulated by a two-layer, depth-integrated Boussinesq model in this paper. The proposed numerical model is verified by a comparison with the experimental results from Synolakis＇s experiment （1986）. The numerical results shows that the layer, depth-integrated Boussinesq model can be applied to study the wave runup and rundown with high precision. The proposed numerical model can predict the solitary wave runup and rundown movement. The wave amplitude in the runup is smaller than those in the experiments. The inclusion of an accurate bottom friction parameterization seems to become increasingly important with increasing degree of wave breaking, probably due to the fact that as a broken wave runs up a mild slope, it travels up the slope as a fairly thin layer of water. The smaller the total water depth, the more important the bottom friction becomes.