Broadband shock-associated noise modelling for high-area-ratio under-expanded jets

Broadband shock-associated noise (BBSAN) is an important component of supersonic jet for jets at off-design conditions when the pressure nozzle exit different from ambient. Two high-area-ratio under-expanded ratios (NPRs) 3.4 and 4.2 are considered. The correspond to experiment in Laboratory Turbulence Research Aerospace Combustion (LTRAC) Supersonic Jet Facility Monash University. Flow solutions obtained by large eddy simulation (LES) Reynolds averaged Navier–Stokes (RANS) methods. validated against particle image velocimetry (PIV) data. For spectra predictions, LES solution combined with time-domain Ffowcs Williams–Hawkings method. To probe accuracy reduced-order method based on acoustic analogy, RANS substituted Morris Miller BBSAN method, where options modelling correlation scales investigated. predictions compared experimental data non-anechoic LTRAC facility NASA empirical sJet model. Apart low frequencies influenced mixing noise, RANS-based align those most range Strouhal numbers (St) 0.4 < St 2 within 1–2 dB.