Validity of a non-parallel flow asymptotic theory for the adjoint vector Green's function within the generalized acoustic analogy

Afsar, M. (Speaker)

Activity: Talk or presentation typesInvited talk


We examine the validity of an asymptotic scaling to determine the propagator of the acoustic analogy at frequencies of the order of the small jet spread rate. The theory shows that the adjoint linearized Euler equations reduce to a hyperbolic partial differential equation (PDE) in which mean flow non-parallelism enters the lowest order propagator solution through the streamwise component of the mean flow advection vector. Our results show a very good level of accuracy up to a Strouhal number of about 0.6 for polar observation angles in the peak noise direction for supersonic jets at Ma=1.5 and allows a rational explanation for the quietening of heated jets that have been observed at this Mach number.
Period1 May 2019
Held atTel Aviv University, Department of Mechanical Engineering , Israel
Degree of RecognitionInternational


  • Aeroacoustics
  • Asymptotic analysis