Hydrodynamic/acoustic splitting approach with flow-acoustic feedback for universal subsonic noise computation

A generalized approach to decompose the compressible Navier-Stokes equations into an equivalent set of coupled for flow and acoustics is introduced. As a significant extension standard hydrodynamic/acoustic splitting methods, provides essential coupling terms, which account feedback from flow. unique simplified version split equation system with derived that conforms in subsonic regime, where reduces one additional term momentum equation. Subsonic simulations are conducted flow-acoustic cases using scale-resolving run-time hierarchical Cartesian mesh solver, operates different explicit time step sizes incompressible acoustics. The first simulation case focuses on tone generic flute. With major included, yields characteristics agreement reference results K\"uhnelt based Lattice-Boltzmann simulation. On contrary, hybrid method feedback-term switched off lacks proper tone. second case, thick plate duct studied at various low Mach numbers around Parker-beta-mode resonance. reveal mechanism very good experimental data Welsh et al. Simulations theoretical considerations does not reduce stable convective size equations.