An Unstructured Moving Grid Scheme for Shock Impacting on Material Interface

Abstract

An unstructured moving grid scheme is applied to track the real-time motion state of the material interface with large-scale deformation induced by shock in the compressible multi-material flow. The material interface is denoted as a special internal boundary which is made up of unstructured grid edges, and on both sides of that there exist grids used for the two different materials. Riemann problem is solved in order to track the motion of the grid points on the material interface, and the local re-meshing technique is also applied to cope with the large-scale deformation of the moving grids near the interface, especially for the case of strong shocks existing in the multi-material flows. Simultaneously, the material interface is also defined as a kind of grid-deforming boundary in case grid volumes are negative. To obtain the resolution of the whole multi-material flow domain, the arbitrary Lagrangian-Eulerian (ALE) is discretized using Harten-Lax-van Leer-Contact (HLLC) scheme. Several numerical calculations from shock-interface examples demonstrate that this moving grid technique is feasible and effective in tracking the real-time motion state of the material interface.