RANS Closure Model Assessment using LES /RANS Datasets for a Hypersonic Crossing-Shock Interaction

Reynolds-averaged Navier-Stokes (RANS) simulations and scale-resolving (large eddy simulation (LES), hybrid LES/RANS) simulations of a Mach 8.3 crossing-shock interaction are presented in this work. The RANS models tested (Menter BSL and SST) display expected deviations in predictive capability for wall pressure and heat transfer – the scale-resolving strategies fare somewhat better but still show discrepancies that are partially due to the inability of the tested models to predict the effects of shock / boundary layer interactions on the fins, which generate the primary shock system. A wall-resolved LES technique provides the best predictions of surface heat transfer – the inclusion of a RANS component leads an over-prediction of heat transfer in regions away from the centerline. Results from the scale-resolving techniques are ‘data mined’ to extract quantities relevant to RANS-level modeling, including eddy viscosities characteristic of momentum transfer, the Reynolds-stress anisotropy tensor, and its second invariant, which is used as a 3D analogue of the structure factor found in Menter’s SST model. The results echo those of our earlier studies of 2D / axisymmetric hypersonic SBLIs in that substantial increases in the structure factor occur in the vicinity of the primary separation shock. A reconstruction of the Menter SST eddy viscosity that considers this variation is shown to provide better agreement with a ‘least squares’ eddy viscosity derived by equating the actual turbulence production with that modeled using a Boussinesq assumption.