基于动态混合网格的不可压非定常流计算方法

Implicit algorithm based on dynamic hybrid mesh for incompressible unsteady flows

摘要: 鱼类、昆虫等运动速度较低，对它们的数值模拟需要解决不可压问题. 虚拟压缩方法通过在连续性方程中加入压强对虚拟时间的偏导数，从而把压力场和速度场耦合起来，解决了不可压缩流的计算问题. 基于动态混合网格技术，利用双时间步方法耦合虚拟压缩方法来解决非定常不可压缩流的计算问题. 为了加快每一虚拟时间步内的收敛速度，子迭代采用了高效的块LU-SGS方法，并且耦合了基于混合网格的多重网格方法. 利用该方法数值模拟了不同雷诺数下的静止圆柱、振荡圆柱的绕流，得到了与实验和他人计算一致的结果.

Abstract: An implicit solver for incompressible unsteady flows is presented,based on the dynamic hybrid mesh proposed by the authors previously. Thesolver is based on an artificial compressibility method with dual-timestepping for time advancing. To accelerate the convergence insub-iterations, we use a block LU-SGS coupling with the multi-gridtechnique based on hybrid grids. Several typical cases are simulated tovalidate the flow solver. The numerical results show the efficiency andaccuracy of the solver for incompressible unsteady flows.