Numerical predictions of high speed jet noise

A parallel three-dimensional computational aeroacoustics method, based on large eddy simulation and a split between the mean flow and perturbations, has been developed to predict the unsteady characteristics of supersonic jet flows and their radiated noise. The instantaneous quantities are decomposed into a time-independent mean component, a large-scale perturbation, and a small-scale perturbation. Only the large-scale fluctuations are resolved directly while the mean quantities are obtained from a traditional Reynolds averaged method. The effects of the small-scale fluctuations are parameterized using a subgrid scale model. In order to reduce the wall-clock time for the simulations, the three-dimensional code has been parallelized using a domain decomposition strategy and Message Passing Interface (MPI) routines are used to facilitate exchange of data between different processors. Results for both the flow and acoustic fields of a circular jet simulation at a nozzle exit Mach number of 2.1 are presented and comparisons with several experimental measurements are made.