Exploring the validity of Spalart-Allmaras Turbulence Model for Hypersonic Flows

The Spalart and Allmaras turbulence model has been implemented in a finite volume code using an implicit finite difference technique. First, the implementation was validated on flat plate turbulent boundary layer flows under various flow conditions. Then, three high speed flow applications characterized by different turbulent phenomena have been considered to investigate the behavior of the Spalart Allmaras model in the hypersonic regime, namely a hypersonic wind tunnel flow, a Mach 5 flow over a hollow-cylinder-flare and a Mach 6.8 flow over a hyperboloid-flare. Numerical results were found in excellent agreement with experimental data for the attached nozzle flow and the hyperboloid flow involving laminar separation and turbulent reattachment. For the hollow-cylinder flare configuration which involves turbulent separation, the magnitude of surface pressure and of heat transfer peaks were correctly predicted whereas their positions were slightly incorrect due to the underprediction of the separation bubble size