Hybrid Aeroacoustic Simulations of a Heated Mach 2 Jet

Direct modelling of the propagation of noise is computationally expensive due to the requirement of capturing both the propagation of acoustic waves over long distances and the small turbulent length scales from which they originate. On the other hand, the Ffowcs Williams-Hawking analogy is constrained to modelling sound propagation in a uniform acoustic medium. In this paper, a hybrid computational aeroacoustic approach is presented in which a large eddy simulation (LES) is paired with the solution of the acoustic perturbation equations (APE) for the acoustic simulation in a non-uniform acoustic medium. This work highlights some persistent difficulties in the coupled LES/APE hybrid approach to computational acoustics, specifically numerical instabilities encountered when solving the APE system with a high-order spectral code on a base flow featuring strong shocks and thin initial shear layers. Nevertheless, the computational efficiency of the coupled method is demonstrated, with the two solver executables maintaining up to 90% of their ideal un-coupled run-time performance when running in parallel.