GENERATION OF STREAMWISE STRUCTURES BY EXTERNAL VORTICAL AND THERMAL WAVES

Streamwise structures generated by external vortical and thermal waves in subsonic and supersonic boundary layers have been studied. Particular attention is paid to the formulation of the boundary conditions at the outer edge of the boundary layer. It has been found that the disturbances of the boundary-layer streamwise velocities can be several times larger than the amplitude of the external vortical wave. The generation efficiency decreases with increasing Mach number. It has been shown that the influence of thermal external waves on the boundary-layer flow structure is much weaker than the influence of the vortex structure of the flow.