An exploration of standard turbulence models for modelling shock-boundary layer interaction in high speed intakes

Shock-wave boundary layer interactions are ubiquitous in high speed intakes and are responsible for steep thermal gradients and unfavourable viscous interactions such as buzz and unstart. Predicting these interactions is an essential part in the iterative design process. Currently, Reynolds-Averaged Navier Stokes (RANS) approaches are noted to be deficient in their applicability to separation and strong gradients due to their inability to capture the unsteadiness. Nonetheless, RANS approaches are preferred by industry due to their relatively quick convergence times and ability to capture mean flowfields. There also exist limited geometries that can be used for validation purposes. This research compares the Spalart-Allmaras and the kω-SST turbulence model for their ability to predict key interactions in a novel Mach 6 mixed compression axisymmetric hypersonic intake. As part of studying the interactions, a laminar double wedge geometry, indicative of a 2D ramp intake is also studied to compare numerical methods in predicting laminar interactions. Two codes are used, ANSYS Fluent and the University of Sydney in-house research code, Flamenco. Flamenco is found to perform better for laminar interactions in the double wedge geometry compared to Fluent due to its high-order scheme. In turbulent interactions the kω-SST model is found to predict a larger separation zone compared to the SA model. Both models have reasonable agreement with the experimental data. This research provides an additional geometry that can now be used for validation cases to further modelling approaches and the state-of-the-art