Crossflow effects on shock wave/turbulent boundary layer interactions

The effects of crossflow on the interaction between an impinging shock wave and a high-speed turbulent boundary layer are investigated using direct numerical simulations of statistically two-dimensional, three-component flow. The leading-order effect of crossflow is increased size and strength of the separation bubble, with upstream and downstream displacement of the separation and reattachment points, respectively. This effect is traced to retarded growth of the shear layer surrounding the separation bubble, with associated reduction of the turbulent shear stress. Genuinely, three-dimensional effects are observed in the interaction and in the downstream recovery zone, with mean flow direction changing both in the longitudinal and wall-normal directions. Three-dimensional, non-equilibrium effects yield substantial misalignment between turbulent stresses and mean strain rate, thus providing a challenging benchmark for the development and validation of turbulence models for compressible flows.