Analysis of Hydrodynamics and Noise Prediction of the Marine Propellers under Cavitating and Non-cavitating Conditions

Abstract

Marine propeller hydrodynamics and noise study is an important problem in the suitable performance of ships and submarines. In the first step of this paper, the hydrodynamics of two propellers was studied under different operating conditions.Thensheet cavitation inception and development conditions were obtained in order to understand the impact of varying rotational speed of the propeller and pressure drop on the propeller noise. In the second step overall sound pressure levels (SPLs) under non-cavitating and sheet cavitating conditions were extracted for each of these models. The overall SPLs were calculated from Ffowcs Williams and Hawkings(FW-H) equations and its integral solutions. In this work, the flow field was analysed with the FVM, and then flow data including; pressure fluctuations, sheet cavitation volume and velocity magnitude results of the flow solution were used as the input for the FW-H formulation to predict the overall SPLs. The results from flow analysis are significant since they are used as noise sources in the FW-H equations to obtainthe overall SPLs. Therefore, these results must be thoroughly analysed. The numerical hydrodynamics results were compared with experiment results for the two propellers and a good agreement was found.