Knowledge Bank

Difficulty in experimental study and limited flight test data makes computational fluid dynamics (CFD) a critical tool in understanding the hypersonic flow regime. Key factors influencing predictive accuracy are the computational grid configuration and the solver used. A sensitivity study is conducted by varying: 1) grid type (unstructured vs. structured), 2) mesh resolution, and 3) CFD solver (ANSYS Fluent vs. NASA Langley FUN3D). The differences are highlighted by considering a simple configuration, namely a double-wedge airfoil. Metrics for comparison include inviscid and viscous pressure profiles, inviscid and adiabatic wall temperature, and heat flux profile over an isothermal wall at 300K. No strong sensitivity is observed for mesh configuration or solver for the pressure in inviscid flow. Furthermore, numerical and theoretical predictions are in close agreement. Notable deviations are observed for viscous flow, particularly between the two solvers. This is most evident in terms of adiabatic wall temperature and heat flux distributions.