Overview of the Use of Large-Eddy Simulations in Jet Aeroacoustics

The current state of the use of large-eddy simulations (LESs) in jet aeroacoustics is reviewed. Various computational techniques are discussed, as well as methods to extend the LES results to the acoustic far field. As the computational power increases and computational techniques mature, LES-based calculations are becoming more realistic by including complicated nozzle shapes and by increasing the Reynolds numbers to approach flight conditions. The LES is now being used for evaluation and the understanding of noise mechanisms from heated or unheated, subsonic or supersonic, and single or multiple jets (for example, twin jets). Also, impinging jets, jet blast deflector surfaces, installation effects, and noise reduction strategies (for example, fluidic injection, plasma actuators, chevrons, and beveled nozzles) are currently being studied and evaluated. Thus, the LES is becoming a useful and versatile design tool for the aerospace industry, and it is expected that its use for jet noise prediction will keep increasing.