等波高双孤立波直墙爬高的数值模拟

基于RANS方程、VOF方法以及修正的Goring造波方法建立了模拟活塞式推波板运动的二维数值波浪水槽，实现了双孤立波直墙爬高的数值模拟．利用动边界技术模拟造波机推波板的运动，有效地实现了不同波峰间距双孤立波的造波方法．在验证单孤立波直墙爬高的基础上，模拟了不同相对波高、相对波峰间距的等波高双孤立波的直墙爬高过程，给出了波面、速度场及波动能量的变化规律．数值模拟结果表明：对于等波高的双孤立波，当入射波波高较大及两个波峰间距相对较小时，跟随在后孤立波的爬高放大系数小于先导孤立波的爬高放大系数；双孤立波在直墙爬高过程中，波动场的势能时间过程线呈现三峰形态，其中居中的最大势能峰值出现在第二个孤立波与经直墙反射后反向传播的第一个孤立波完全对撞的时刻．

Numerical Simulation of Run-up of Double Solitary Waves with the Same Height on Vertical Wall

A two-dimensional numerical flume was established based on the mathematical model of the incompressible, viscous flows with the free surface. The governing equations were the Reynolds averaged N-S equation and the conservation equations of the Volume of Fluid function. The modified Goring approach and the moving boundary technique were used to implement the movement of the paddle of waver maker and generation of the double solitary waves with different distance between two crests. By comparing the computed maximum run-up with theoretical value, the numerical analysis of single solitary wave run-up against a vertical wall was carried out to validate the numerical wave flume. For the run-up of the double solitary wave with different relative height and crest distance, the time series of surface elevation of the double solitary waves were given in the constant depth region and moving waterline on the vertical wall, the changes of the wave surface, velocity field and energy were obtained and analyzed. It turns out that，for the case of the double solitary wave with the same height, the run-up amplification coefficient of the second solitary is smaller than that of the first one. There are three peaks in the time series of the total potential energy of the wave field during the period of the double solitary wave’s run-up.