Cancellation effects introduced by the “enthalpy flux– momentum flux” coupling term in the acoustic spectrum of heated flows at supersonic speeds

Accurate prediction of the jet noise in heated flows is of considerable interest. In this paper, we develop a self-consistent model for the jet noise in heated flows using the generalized acoustic analogy derived by Goldstein [2003]. As opposed to previous models, we do not neglect the “enthalpy flux – momentum flux” covariance (or the coupling term). Theory shows, the coupling term can give a cancellation to the acoustic spectrum when the acoustic Mach number is supersonic and the observation point is close to the jet axis. The coupling term, therefore, provides a new and simple means of jet noise reduction.