Computational fluid dynamics nose-to-tail capability - Hypersonic unsteady Navier-Stokes code validation

Computational fluid dynamics (CFD) research for hypersonic flows presents new problems in code validation because of the added complexity of the physical models. This paper surveys code validation procedures applicable to hypersonic flow models that include real-gas effects. The current status of hypersonic CFD flow analysis is assessed with the compressible Navier-Stokes code as a case study. The methods of code validation discussed go beyond comparison with experimental data to include comparisons with other codes and formulations, component analyses, and estimation of numerical errors. Current results indicate that predicting hypersonic flows of perfect gases and equilibrium air are well in hand. Pressure, shock location, and integrated quantities are relatively easy to predict accurately, whereas surface quantities such as heat transfer are more sensitive to the solution procedure. Modeling transition to turbulence needs refinement, although preliminary results are promising.