时刻追踪多介质界面运动的动网格方法

Moving grid method in numerical simulation of compressible multi-material flows

在对可压缩多介质流动的数值模拟中,定义介质界面为一种内部边界,由网格的边组成,界面边两侧对应两种不同介质中的网格。通过求解Riemann问题追踪介质界面上网格节点的运动,同时采用局部重构的动网格技术处理介质界面的大变形问题,并将介质界面定义为网格变形边界,以防止该边界上网格体积为负。运用HLLC格式求解ALE方程组得到整个多介质流场的数值解。最后从几个多介质流模型的计算结果可以看出,本文的动网格方法是可行的,而且可以时刻追踪介质界面的运动状态。

In the numerical simulation of compressible multi-material flows, the material interface is defined as a special internal boundary composed by unstructured grid edges, either side of which corresponds to a grid of one material. Riemann problem is solved in order to track the motion of the grid points on the material interface and local re-meshing technology is applied to deal with the large-scale de- formation of the moving grids. At the same time, the material interface is defined as a kind of grid-deforming boundary to avoid negative grid volumes near the interface. HLLC scheme is used to solve ALE formulations to obtain the resolutions of the whole multi-material fluid domain. Several multi-material modules are computed to indicate that the method in this paper is feasible and successful in tracking the motion state of the material interface.