Slow mode

Prediction and control of the hypersonic boundary-layer transition from a laminar to a turbulent state are vital to developing future hypersonic systems – capable of reaching at least Mach 5, or approximately 3,800 mph.

The appearance of instability waves near the nose region and the receptivity of the boundary layer with respect to slow mode acoustic waves are investigated. Computations confirm the stabilizing effect of nose bluntness and the role of the entropy layer in the delay of boundary-layer transition.