复杂边界下同位网格和交错网格水流模型收敛性

为提高计算精度,研究简单和复杂边界情况下交错网格和同位网格平面二维水流模型的收敛性。采用有限体积法离散正交曲线坐标下的控制方程,使用S IM PLEC方法求解水位。比较水流动能、最大水位修正和剩余质量源随迭代的变化过程。结果表明:1)在简单边界条件下,交错网格模型收敛性较好;2)在复杂边界条件下,两套网格模型收敛性基本相同。在恒定流计算过程中采用动能标准比最大水位修正和剩余质量标准更能有效地判别模型的稳定性。

Convergence of flow models using staggered and collocated grids with complicated boundaries

The convergence rates of two depth-averaged 2-D flow models using staggered and collocated grids were compared for both simple and complex geometries to improve the calculation accuracy.The finite volume method was used to discretize the governing equations on the orthogonal curvilinear coordinate system with the SIMPLEC method to solve for the water level distribution. The convergence rates for the two models were analyzed based on the variation processes of the kinetic energy,the maximum water level changes,and the residual mass during the iterations. The results show that the staggered grid model performs better in terms of stability and convergence for simple boundaries with the two models almost the same for the complicated boundaries.The kinetic energy criterion more effectively represents the model stability in steady flow simulations than the maximum water level variations or the residual mass criterion.