基于子网格边界近似Riemann解的人为粘性方法

An Artificial Viscosity Based on the Subcell-Edged Approxim ate Riemann Solver

在交错网格型Lagrange(拉格朗日)流体力学算法中,通常采用人为粘性捕捉激波,人为粘性的好坏对于计算结果至关重要.研究了一种基于子网格边界处近似Riemann解的新型人为粘性.新人为粘性能够满足动量守恒和熵不等式.利用子网格边界速度差中引入的限制器,新人为粘性能够区分激波和等熵压缩,并能满足球对称问题中的波面不变性.新人为粘性在典型模型数值模拟及惯性约束聚变黑腔整体数值模拟中取得了较好的结果.

The artificial viscosity method is generally used to capture shock waves in the La- grangian hydrodynamics algorithms, and the properties of the artificial viscosity influence the simulation results essentially. A new artificial viscosity based on the subcell-edged approximate Riemann solver was presented. This new method was prove to have the merits of momentum conservation and satisfaction of entropy inequality. With the introduced limiters for the differ- ences of velocities on the subcell edges, the presented artificial viscosity is able to distinguish the shock wave from the isoentropic compression and satisfy the wave front invariance in the spherical symmetric problems. Various numerical examples demonstrate the robustness and ef- fectiveness of the new artificial viscosity.