Transition onset predictions for oblique breakdown in a mach 3 boundary layer

Boundary-layer transition has important implications for the aerodynamic design of supersonic and hypersonic flight vehicles due to the accompanying increase in aerothermal loads. For developing accurate and reliable tools for predicting the transition location, the physics of the transition process must be well understood. The receptivity behavior of the laminar Mach 3 boundary layer is investigated using the receptivity module within LASTRAC. This module can be used for making integrated predictions of receptivity and the subsequent evolution of instability waves for certain simple classes of receptivity mechanisms including the receptivity to unsteady blowing and suction at the surface as applied in the DNS. Good agreement was found for all stages of transition, including receptivity, linear and nonlinear disturbance evolution, and the onset of the breakdown process until the mean wall shear had nearly doubled with respect to its laminar value. Hence, the PSE approach can correctly predict the transition onset via oblique breakdown.