Aeroacoustics of Supersonic Boundary Layers

Abstract

Present paper is devoted to those acoustical problems which are also related to the problem of the turbulence onset in high-speed boundary layers. Basic equations governing linear development of both hydrodynamic and acoustic waves in high-speed boundary layers are presented. Results of the theoretical investigation on external acoustic wave influence on the flat plate boundary layer are described. The intensity of disturbances excited by an acoustic wave inside the boundary layer has been studied. It has been found that interaction of sound with the boundary layer lead to an increase of the amplitude of disturbances inside the boundary. It has been shown that the amplitude of fluctuations inside the boundary layer may exceed the amplitude of the external acoustic field in many times. Besides in the paper nonlinear generation of increasing perturbations by acoustics is studied.