Ricerc@Sapienza

We perform direct numerical simulations of shock-wave/boundary-layer interactions at Mach number M = 1.7 to investigate the influence of the state of the incoming boundary layer. The flow configuration includes a spatially evolving laminar boundary layer that is tripped by an array of distributed roughness elements and impinged further downstream by an oblique shock wave. Four SBLI cases are considered, based on two different shock impingement locations, corresponding to transitional and turbulent interactions, and two different shock strengths (3,6 deg). We find that, for all flow cases, shock-induced separation is not observed, the boundary layer remains attached at phi = 3 and close to incipient separation at phi = 6, independent of the state of the incoming boundary layer. The extent of the interaction zone is mainly determined by the strength of the interaction, and the state of the incoming boundary layer has little influence on the interaction length scale $L$. Scaling analyses for $L$ available in literature for turbulent interactions are found to be equally applicable for the transitional interactions. The findings of this work suggest that a transitional interaction might be the optimal solution for aerospace applications involving SBLI.