Large Eddy Simulation for Jets from Chevron and Dual Flow Nozzles

Large eddy simulations based on high-order finite d ifference schemes have been carried out for jet flows from a NASA ARN2 circular and a SMC001 chevron nozzle at acoustic Mach 0.9. Simulations have also been carried out fo r a bypass ratio 5 dual-flow nozzle at a typical take-off condition. Implicit LES approach i s applied, wherein high-order numerical filters are used in place of SGS models. Far field noise spectra are computed from near field flow solutions with the use of the FWH method. Numerical experiments are conducted to explore the sensitivity of the predicted flow and a coustic field to grid size. Good agreement with experiment data is achieved for both flow and acoustic predictions at moderate grid sizes. It is shown that the first-principles based implicit LES approach can capture the effect of chevron geometry on the far-field acoustics. The predicted noise reduction trend is in good agreement with the experimental data. The LES approach has also been demonstrated for a dual flow realistic engine configuration