Large Eddy Simulations of Hot Supersonic Jets for Aeroacoustics

LES will be used to calculate flow and noise issuing from realistic engine configurations such as realistic engine nozzle throats, serrated nozzles, straight ramp diffusers, and over/under expanded operation. Nozzle geometry and operating conditions can be specified by the government with the objective of validating noise prediction capability on the basis of realistic parameters. Where necessary, additional testing will be conducted by UTRC to generate data sets representative of military engines entering into service today. LES results will be used to provide data to improve the fidelity of nonlinear PSE models. These models will be exercised in order to investigate how nozzle design affects the mechanisms of noise radiation. Compared to Phase I, a more rigorous data processing routines to much longer time series from LES will be conducted, we will run more NPSE cases with higher numbers of modes and to insure that there are not convergence problems with the PSE approach. In addition, modeling of nonlinear effects in PSE models will be supplemented with sub-grid-scale models to account for interaction of wavepackets with fine-scale turbulence.