Effects of reynolds stress on flow noise from vortex/hydrofoil interactions

Acoustic field generated by a single vortex approaching a hydrofoil is studied. A combined vortex/RANS simulation for the near-field unsteady vorticity is developed to include effects from RANS Reynolds stresses. The far-field acoustics is calculated using a vortex sound formula with the near-field vorticity as the source. The results show that at a higher incident angle when the RANS shows a substantial region with strong Reynolds stresses, there is a significant increase in the sound level due to enhanced unsteady vorticity in the shed vortices near the trailing edge.