Abstract:

At sound excitation of a supersonic shear layer, disturbances arise there which can radiate Mach waves at supersonic values of the convective movement velocity. In this paper, results are presented of experimental investigations of the action of the finite-amplitude saw-toothed sound waves on the mixing layer of a supersonic air jet issuing from a conical supersonic nozzle designed for M=2.0 at different sound incidence angles onto the jet boundary. It is shown that sound radiation by the excited jet at the external excitation frequency is associated with Mach wave radiation, its directivity is independent of the sound incident angle, and its intensity may exceed the sound intensity in the incident wave by the value up to 20 dB. The amplification value depends on the total pressure in the jet and the sound incidence angle depends on the jet boundary.