Numerical modelling of unsteady cavitation and induced noise around a marine propeller

Abstract

The objective of this paper is to numerically investigate the cavitating flow around a marine propeller and to explore the intrinsic relationships between the sheet cavitation and its radiation noise. The k-ω SST turbulence model with the turbulence viscosity correction and the Zwart cavitation model are introduced to the simulation of cavitating flow around a propeller in a non-uniform wake. The loading noise and cavitation noise have been predicted based on the theory for acoustic fan source and the sound radiation theory for spherical bubble respectively. The periodic cavitation development has been captured, and the periodic large pressure fluctuation around the blade has been analyzed with the dominant frequencies in accordance to the first order of the blade passing frequency. For the non-cavitation case, the high sound pressure levels mainly concentrate in the low frequency stage and decrease from the low-order to the high-order blade passing frequency. While for the sheet cavitation case, the sound pressure level at the high-order of blade passing frequencies are enhanced. The sound pressure induced by the cavitation development is periodically varied accompanied with the periodic pulsating cavity evolution, and the acoustic energy mainly focus on the low order of blade passing frequencies.