Modeling of sound propagation in flow

Abstract: The propagation of sound waves in the presence of flow is encountered in a wide range of fields in physics. Examples include infrasound waves in the Earth's atmosphere, indirect combustion noise, and sound radiation from free turbulent flows or wall-bounded flows in vibro-acoustics. If we wish to move away from a direct approach using compressible direct numerical simulation of fluid mechanics equations, we are quickly confronted with the coupling between acoustic waves and other modes of fluctuation (gravity waves, entropic waves, and vorticity waves) in a linear approach. After a brief historical review of the modeling of acoustic propagation in flow, we will seek to demonstrate the value of constructing a solution based on a self-adjoint formulation of the problem. The objective will then be to obtain the best possible approximation, allowing us to preserve the physical properties of sound propagation in flow and thus better characterize the intrinsic properties of sources in aeroacoustics, for example.