SIMULATION OF SUPERSONIC JET NOISE WITH NONLINEAR CFD AND KIRCHHOFF SURFACE INTEGRAL

An acoustic prediction capability for supersonic axisymmetric jets was developed on the basis of the OVERFLOW Navier-Stokes CFD (Computational Fluid Dynamics) code. Reynolds-averaged turbulent stresses in the flow field are modeled with the aid of Spalart-Allmaras one-equation turbulence model. Appropriate acoustic and outflow boundary conditions were implemented to compute time-dependent acoustic pressure in the nonlinear source-field. Based on the specification of acoustic pressure, its temporal and normal derivatives on the Kirchhoff surface, the near-field and the far-field sound pressure levels are computed via Kirchhoff surface integral, with the Kirchhoff surface chosen to enclose the nonlinear sound source region described by the CFD code. The method is validated by a comparison of the predictions of sound pressure levels with the available data for axisymmetric turbulent supersonic perfectly expanded jets.