Hypersonic boundary-layer receptivity and stability

The response of a hypersonic boundary-layer to external forcing is computed by solving compressible linearized Navier-Stokes (CLNS) equations. Mach 8 flow past a sharp wedge is considered and calculations are performed for a fixed disturbance frequency with localized wall suction/blowing. Wave modulation due to the boundary-layer modes associated with slow and fast acoustic waves occurs but the unstable second mode eventually results. Stability results are also presented for Mach 22 flow past a 22 degrees half-angle cone using PSE analysis with finite-rate chemistry. The value of N factor found at the onset of transition is about 11.3 for the hypersonic flight experimental data.