Simulation of transitional shockwave/boundary-layer interaction using advanced RANS-based modeling

A set of RANS and hybrid RANS/LES simulations were run to investigate the upstream flow field of a laminar-turbulent transition shockwave/boundary-layer interaction generated by a cylinder. Both fully turbulent and transitional RANS simulations were run, and used the one-equation, Spalart-Allmaras (SA) eddy-viscosity model along with an amplificationfactor-transport transition model. Neither the fully turbulent nor transitional RANS simulation meet the steady-state convergence criterion, and an inherent unsteadiness was present in the solution. Time-accurate simulations of both models were run showing no change in the relevant flow features. Both models showed agreement of major flow phenomena with empirical data, but the fully turbulent SA model failed to predict the upstream influence shock. Additionally, time-accurate delayed detached eddy simulation was performed, predicting unsteadiness in the separation bubble that consisted of several smaller vortices rather than a larger single vortex as predicted by RANS simulations. Furthermore, the forward shock and triple point height fluctuated based on the movement of the separation bubble.