三棱柱形网格下自由表面流的三维数值模拟

3D numerical simulation of free surface flow on tri-prism grids

为了模拟自由表面流动问题,建立了基于三棱柱形网格的三维Navier-Stokes方程的半隐式动压离散模型。出流边界采用在动量方程右端附加线性衰减项的海绵层处理方式来消减波能。引入k-ε双方程紊流模型求解涡黏性系数,使方程达到封闭。用规则周期波通过淹没障碍物的传播变形和复合明渠流动算例,验证了当遇到短波高频问题时,所述模型模拟结果与测量值吻合良好,体现了模型的精确性和有效性。

In order to simulate the free surface flow problem, a 3D Navier-Stokes equation based on the tri-prism grid is established, which has the hydrodynamic pressure model and the semi-implicit numerical discrete format. At the outflow bound- ary, we add the linear attenuation terms of sponge layer processing to the right-hand of the momentum equations to reduce the wave energy. We use the κ-ε turbulent equation to solve the eddy viscosity coefficient in order to close the model. The numerical tests include the simulation of regular period wave propagation over a bar and the compound open channel situation. While tackling the short-wave high frequency problem, we found that the results are in good agreement with the analytic solutions or the measured values, which shows the accuracy and validity of this model.