An h-Adaptive Solution of the Spherical Blast Wave Problem

Abstract

Compressible flow problems usually exhibit features in the flow field that need a very refined mesh in order to achieve an acceptable accuracy in the numerical solution. Uniform refinement of the whole mesh quickly becomes prohibitive in three dimensions. In these situations, the use of an adaptive technique shows advantageous. Here, a h-refinement/coarsening strategy for unstructured finite element meshes is described and applied to solve the spherical blast wave problem driven by a point-like intense explosion. The resulting meshes are non-conformal. A 3-D refinement constraint is introduced to enforce a smooth size distribution among neighbor elements in the mesh and a gradient error indicator based on the flow variables is used to track discontinuities. It is shown that the adaption strategy allows to improve the accuracy and to reduce the spurious oscillations in the numerical solution, requiring just a small fraction of the overall computing time.