Model and Full Scale Measurements of Propeller Cavitation Noise on an Oceanographic Research Ship with Two Different Types of Screw Propeller

Abstract

In designing naval or oceanographic research ships, reduction of underwater noise radiated from the ship is of primary importance to secure the reliable operation of acoustic instruments. Among various hydrodynamic and mechanical noise sources, propeller cavitation is considered to be the most harmful for acoustic survey operation, since its dominant noise levels cover a wide frequency band. Thus the design of the propeller for such ships requires great care. In this study, two different propellers, A and B, were designed for an oceanographic research ship. Cavitation patterns and radiated noise characteristics of both propellers were investigated by means of model tests in a cavitation tunnel. Also field measurements were performed to compare the radiated noise level of both propellers on full scale. Scaling of the noise data measured in the cavitation tunnel was done using an existing hydro-acoustical model of cavitation noise.