AUTOMATIC DIRECTIONAL REFINEMENT IN ADAPTIVE ANALYSIS OF COMPRESSIBLE FLOWS

In such local phenomena as shocks and boundary layers, etc, the discretization errors are directional and the use of elongated elements is obvious if economy is to be achieved. Although facilities for local mesh elongation have been incorporated into earlier codes in generating unstructured meshes, these do not permit the use of very high stretch ratios required for the analysis of such problems as boundary layers. Here the use of locally introduced structured meshes has been practised involving much manual interaction and loss of error control. In the paper we present a procedure which achieves the combination of such locally structured meshes with a general unstructured mesh generator in an automatic and fully adaptive manner. The procedure is illustrated in the context of compressible, viscous and inviscid, flows but has obvious applications in other (solid mechanics) problems involving localization.