On the prediction of near-field cavity flow noise using dif- ferent CAA techniques

Since the direct numerical simulation (DNS) of aeroacoustic noise requires the numerical solution of the compressible Navier-Stokes equations in a large computational domain, it is computationally too demanding to solve computational aeroacoustics (CAA) applications using this technique only. In this paper a number of different hybrid approaches, where the computational domain is split into a source region and a propagation region, are used to solve the aerodynamically generated sound field by a flow over a rectangular cavity. In cavity flow noise applications, both broadband and tonal noise is emitted; under certain circumstances the sound field can be considered as 2-dimensional and there are reference solutions available from literature. In this way, a comparison can be made between different hybrid numerical methodologies. This paper focuses mainly on the accuracy of the commonly used equations to describe the acoustic near-field propagation and different coupling techniques between the source region and the propagation region.