Experiments on the stability of supersonic laminar boundary layers

The present paper reports an experimental study of the development of plane monochromatic waves in the boundary layer on a flat plate at Mach number M = 2.0. The wave characteristics of the plane waves are obtained. Three-dimensional disturbances with an angle of the wave vector to the flow χ = 50–70° are found to be the most unstable. It is shown that the disturbances, consisting of vortical and compressible modes, are engendered in a supersonic boundary layer by a local source of artificial disturbances. It is found that an increase in the bluntness of the leading edge of a plate stabilizes three-dimensional disturbances of a vortical mode.