Simulation of Two-Dimensional Multi-Material Compressible Flows Using Lagrangian Methods

When simulating the two-dimensional multi-material compressible flows using the Lagrangian method, the distortion of the mesh is often the reason why the process terminates.The dynamic local remeshing is an option to relax the distortion.In this study, we combined the "diagonal-swapping" "edge-splitting" "edge-merging" and "hat-trick" to deal with the distortive mesh.The 4 operations could act not only in single material, but also be extended to the multi-material interface to deal with the distortive mesh on the interface.After the remeshing, the quantities on the old mesh are projected onto the new one.During this process, the mass, momentum and energy are kept conservative.We verified the effectiveness and accuracy of this method by using it to simulate the shock/bubble interaction and the R-T instability.In the R-T instability simulation, the single material and the multi-material models are applied to prove that this method is able to deal with the distortive mesh both inside the material and on the interface.