Cavity Induced Trip Model for RANS in Hypersonic Flows

A cavity-induced trip model was developed and implemented into US3D to simulate turbulent transition in hypersonic flows. The model leverages experimental wind tunnel data on cavity-induced transition at Mach 6.0 and Mach 10.0, along with local boundary layer data obtained from CFD simulations. The correlation was formulated based on a rectangular cavity volume, boundary layer height, displacement thickness Reynolds number, and edge-to-wall temperature ratio. The correlation yields a single parameter that can be used to determine whether a rectangular cavity will trip the flow. Preliminary results suggest that the correlation may be applicable to other geometries, particularly flat plates of varying pressure gradients at zero angle of attack. CFD simulations were performed to demonstrate the effectiveness of the correlation to differentiate between tripped and untripped flow based on incoming local flow variables and user-specified cavity dimensions. The model does not accurately predict the augmented heat flux caused by the cavity. Future work aims to incorporate a cavity trip strength into the trip model to predict the increase in heat flux and accurately capture the spreading angle of the turbulent region downstream of the trip.