Effect of nozzle lip shape on screech tone in a supersonic jet

The effect of nozzle lip shape on screech tone is investigated by a computational aeroacoustic approach. First, the scattered patterns of screech tone are examined without a jet mean flow, where plane waves interact with a nozzle lip wall. Then, an axisymmetric jet screech is simulated in the Mach number range from 1.07 to 1.2, where the axisymmetric mode is a dominant screech mode. The conservative form of the axisymmetric Euler equations written in generalized coordinates are used to treat the complex nozzle lip geometry for the scattering problem as well as the Reynolds Averaged Navier-Stokes equations with the modified Spalart-Allmaras turbulence model. The computed shock-cell structure, screech tone frequency, and sound pressure levels in the near field are in good agreement with existing experimental data.