Investigation of Cavitation Phenomena on Noise of Underwater Propeller

Abstract

Underwater propeller cavitation noise is composed of tonal blade rate noise and high frequency broadband noise. Cavitation usually increases overall sound pressure level in the various frequency ranges which depends on the type of cavitation. This research had been carry out to predict the radiated noise from a marine propeller in presence of cavitation with various cavitation types. The analysis is performed by coupling an acoustic code based on the Ffowcs Williams-Hawkings (FWH) equation to unsteady Reynolds-averaged Navier-Stokes (URANS) which able to simulate multiphase flows in rotational domains. A brief summary of numerical method used to model the cavitation around the underwater propeller are presented and the thrust and torque coefficients are validated in different flow conditions by experimental results. The radiated noise along the shaft direction and perpendicular to the shaft direction is studied on both cavitating and non-cavitating propellers. Then, to predict the radiated noise due to cavitation in marine propeller, the computed sound pressure level (SPL) for non-cavitating marine propeller is compared with the SPL for the same propeller in cavitation conditions at various cavitation number and advanced coefficients. The noise analysis helps to determine the dominant noise source of the underwater propeller in different conditions, which will provide a basis for proper noise control strategies.