Turbulent mixing noise from supersonic jets

There is now a substantial body of theoretical and experimental evidence that the dominant part of the turbulent mixing noise of supersonic jets is generated directly by the large turbulence structures/instability waves or the jet flow. Earlier, Tam and Burton provided a description of the physical mechanism by which supersonically traveling instability waves can generate sound efficiently. They used the method of matched asymptotic expansions to construct an instability wave solution which is valid in the far field. The present work is an extension or the theory of Tam and Burton. It is argued that the instability wave spectrum of the jet may be regarded as generated by stochastic white noise excitation at the nozzle lip region. The present stochastic wave model theory of supersonic jet noise contains a single unknown multiplicative constant