3D flow computations over blunt bodies at hypersonic speeds using a shock-fitting technique

The numerical simulation of hypersonic flows past blunt bodies by means of shock-capturing solvers is characterized by some critical drawbacks which worsen the solution quality, including stagnation point anomalies, spurious numerical oscillations, the carbuncle phenomenon, and the reduction of the order of accuracy of the solution in the entire region downstream of a captured shock. This paper describes an updated version of an unstructured shock-fitting algorithm for three-dimensional flows based on the GRUMMP (Generation and Refinement of Unstructured, Mixed-element Mesh in Parallel) library and the shock surface extraction and reconstruction process from a shock-capturing solution. The proposed technique is applied to a high speed laminar flow past a sphere, which has been extensively studied in the literature. In particular, the comparison between the shock-fitting and shock-capturing approaches clearly highlights the advantages of shock fitting, since it is able to improve the solution quality in the entire shock layer and over the body surface.