基于两相流理论的低浓度挟沙水流运动数值模拟Ⅱ—数学模型的求解与验证

Simulation of low concentration sediment-laden flow based on two-phase flow theory Ⅱ—Solution and verification

基于非结构网格上控制方程的离散思想,提出了曲线网格上低浓度挟沙水流控制方程离散的新方法.该方法采用有限体积法对控制方程进行离散,用基于同位网格的SIMPLE算法处理水流运动方程中水深和速度的耦合关系,且不需要对控制方程进行坐标转换,因而离散方程的形式简单,物理概念清晰,所得到的离散格式既适用于正交曲线网格还适用于非正交曲线网格,能够适应天然河道这类几何形状复杂的物理边界,从而使编程和计算变得更加简单有效.采用海河流域漳河的实测资料进行了验证计算,计算所得的水位、流速与河床冲淤变形与实测资料基本一致.

A new method for the discretization of the governing equations in curvilinear grid is adopted, which is based on the discretization idea on unstructured grids. The control volume method is used for discretization of the governing equations; and the method of SIMPLE algorithm based on collocated grids is employed to deal with the coupling relationship between water depth and velocity. And the governing equations need not be transformed into the curvilinear ones as before. Besides, this discretization algo- rithm can be applied to either orthogonal curvilinear grids or general curvilinear grids, which makes the algorithm be more adaptable to complicated boundary such as natural rivers. The observed data in Zhanghe River in China is used for verification; and the calculated water level, velocity and river bed deformation data are in agreement with the observed ones.