NEAR AND FAR-FIELD INVESTIGATIONS OF SUPERSONIC JET NOISE PREDICTIONS USING A COUPLED LES AND FW-H EQUATION METHOD

The hot supersonic exhausts of gas turbine engines on mil-itary aircraft generate dangerously high noise levels. The noise levels associated with operating these engines are harmful to air-craft carrier deck personnel as well as detrimental to ship and aircraft structures. In this paper, the supersonic jet exhaust is simulated using Large Eddy Simulation (LES), and the Ffowcs Williams and Hawkings (FW-H) equation transforms the LES so-lution to an acoustic solution in the far-field. A Mach 1.5 labora-tory jet test at United Technologies Research Center- Acoustics Research Tunnel is used as validation for the LES/FW-H method. A grid refinement study was performed with the objective of de-termining the requirements for accurate noise predictions. The finest grid resolution yields the best near and far-field acous-tic prediction. A second LES/FW-H validation case is shown for a twin jet experiment that was performed in the anechoic chamber at University of Mississippi’s National Center for Phys-ical Acoustics (NCPA). The LES/FW-H method is applied to the higher complexity heated twin jet with faceted nozzle profiles, demonstrating the applicability of the method over a wider range of flow regimes. The far-field noise prediction agrees very well with the NCPA experiment, including the prediction of broad-band shock associated noise and jet screech. NOMENCLATURE c0 Sound speed in undisturbed medium dA Differential area element on FW-H surface DJ Jet nozzle exit diamete