Numerical Simulation of Subsonic Jet Noise on Non-Conformal Mesh by Spectral Difference Method

In this study, the noise from a subsonic cold jet with acoustic Mach number 0.9 is simulated with a high order spectral difference solver on non-conformal mesh. To accurately simulate the thin turbulence boundary layer inside the nozzle, the jet plume, and the generated noise, which have vastly different scales, the meshes with different sizes are adopted in the nozzle boundary layer, jet shear-layer and the outside region. An interpolation method based on mortar is proposed for data communication at the interface where the non-conformal mesh is used. This method is validated by inviscid and viscous flow problems to demonstrate its accuracy on non-conformal mesh. The Large Eddy Simulation method is utilized to simulate the turbulence with the Vreman model to account for the unresolved dynamics on the solution. The mean flow results are presented and compared with the experimental data by Bridges et al. [1, 2]. The far field noise is obtained by the Ffowcs Williams-Hawkings integration method. The noise spectra at different observer angles are presented and compared with the experimental data, and a good agreement is obtained.