Helmholtz's Decomposition applied to Aeroacoustics

We discuss the decomposition of a compressible velocity field into vortical and compressible structures and use it as a powerful tool during the post-processing of direct aeroacoustic simulations. In particular, different formulations of the decomposition are presented and the superiority of the vector potential formulation of Helmholtz's decomposition is demonstrated. Finally, the decomposition is applied to a compressible flow field over a rectangular cavity at Mach 0.8.