Large-Eddy Simulation of a Mach 0.75 Jet

A large-eddy simulation (LES) of a compressible nozzle/jet conguration has been car-ried out. A cold Mach 0.75 jet was simulated. The Reynolds number based on the jet velocity at the nozzle exit plane and the nozzle diameter was 50 000. The Favre ltered Navier-Stokes equations were solved using a nite volume method with a low dissipative third order up-wind scheme for the convective uxes, a second order centered difference approach for the viscous uxes and a three-stage second order Runge-Kutta time marching technique. A compressible form of Smagorinsky's sub-grid scale model was used for computation of the sub-grid scale stresses. The calculations were performed using a block structured boundary tted mesh with approximately 3 000 000 cells. The calculations have been performed on a parallel computer, using message-passing interface (MPI). Absorbing boundary conditions based on characteristic variables were adopted for all free boundaries. Velocity components specied at the entrainment boundaries were estimated from a corresponding Reynolds Averaged Navier-Stokes (RANS) calculation. In order to diminish disturbances caused by the outlet boundary a buffer layer was added at the domain outlet. Kirchhoff surface inte-gration has been utilized to obtain far-eld sound pressure levels in a number of observe