非结构网格下两步压力校正算法的潮流模拟

针对非结构网格下的潮流数值计算,采用有限体积法离散基本方程,对流-扩散项离散采用幂率格式,交叉扩散项引入超松弛校正方法,水位校正方程应用Rhie-Chow动量插值思想和SIMPLEC类算法导出.采用两步压力校正法将交叉扩散项单独考虑,以提高模型对高度畸变网格的适应能力.计算结果表明,该处理方法可提高压力欠松弛系数,并能有效改善复杂区域潮流模拟的健壮性.通过对黄浦江感潮河段潮流的模拟,表明该模型的预测结果与实测资料吻合良好,模型对潮流的模拟结果是可靠的.

Two-step pressure correction method for tidal flow simulation with unstructured grids

The finite volume method(FVM) was adopted to discretize basic hydraulic equation for tidal flow simulation with unstructured meshes.The power law scheme was used to calculate convective flux and diffusive flux,the over-relaxed correction approach was employed to calculate cross diffusion flux,and Rhie-Chow's momentum interpolation method along with SIMPLEC procedure was used to derive water level correction equation.In order to improve the numerical robustness of the model under high grid deformation,two-step pressure correction method was applied to calculation of cross diffusion flux separately in the pressure correction equation.The numerical results show that this approach can improve the pressure under-relaxation coefficient and the effectiveness of complicated tidal flow simulation.The tidal flow simulation for tidal reaches of Huangpujiang River shows that the predicted results of the model agree well with the measured data;therefore the tidal flow simulated result of the model is reliable.