RANS simulation of ducted marine propulsor flow including subvisual cavitation and acoustic modeling

Abstract

High-fidelity Reynolds-averaged Navier Stokes (RANS) simulations are presented for the ducted marine propulsor P5206, including verification and validation (V&V) using available experimental fluid dynamics data, and subvisual cavitation, and acoustics analysis using the modified Rayleigh-Plesset equation along the bubble trajectories with a far-field form of the acoustic pressure for a collapsing spherical bubble. CFDSHIP-IOWA is used with the blended k-omega/k-epsilon turbulence model and extensions for a relative rotating coordinate system and overset grids. The intervals of V&V analysis for thrust, torque, and profile averaged radial velocity just downstream of rotor tip are reasonable in comparison with previous results. The flow pattern displays the interaction and merging of the tip-leakage and trailing edge vortices. In the interaction region, multiple peaks and vorticity are smaller whereas in the merging region, there is better agreement with the experiment. The tip-leakage vortex core position, size, circulation, and cavitation patterns for sigma(i)=5 also show good agreement with the experiment, although the vortex core size is larger and the circulation in the interaction region is smaller The simulations indicate globally minimum C-p=-sigma(i)=-8.8 on the suction side of the rotor tip at 84% chord from the leading edge and locally minimum C-p=-6.4 in the tip-leakage vortex at 8% chord downstream of the trailing edge, whereas EFD indicates sigma(i) = 11 and the location in the tip-leakage vortex core 50% chord downstream of the trailing edge. Subvisual cavitation and acoustics analysis show that bubble dynamics may partly explain these discrepancies.