This example considers the flow of air over a geometry representative of a full automobile at a 10-degree yaw.  The problem consists of noise from the attached boundary layers on the vehicle surface and also noise from the separated flow on the side A-pillar regions.

An initial set of statistics for the acoustics solver were established on a standard RANS mesh.  The figures on the right show a visualization of the sound sources, showing the generation in the wake and leeward side A-pillar regions.

The NLAS acoustics solver was then applied using a reduced sub-domain with far-field absorbing layers.  Numerical probes were placed on both the windward and leeward sides of the vehicle, just downstream of the A-pillar.

The flow on the windward side remains attached, with the flow on the leeward side generating a significant separation region, with a concomitant increase in turbulent stresses, giving rise to an increase in sound pressure levels on the leeward face.