Study on prediction methods and characteristics of ship underwater radiated noise within full frequency

Abstract

One trend in ship development is low noise characteristics. As one of the major noise sources of ship underwater radiated noise is the power equipment, it is critical to predict the ship underwater radiated noise caused by power equipment during the design phase. In this study, the incentive spectrums of power plants were obtained by testing on an oil tanker ship, and the hull vibration was calculated and measured in the middle and low frequency. The results show that the calculation model satisfies the accuracy requirement. To calculate the ship underwater radiated noise in the middle and low frequency, the finite element and boundary element method (FE-BEM), finite element and infinite element method (FE-IFEM), and finite element and automatic matching layer (FE-AML) were used, respectively. It is found that the FE-BEM is the preferred method for calculating ship underwater radiated noise in modeling scale and computational efficiency. The calculation of hull vibration and underwater radiated noise in the high frequency were performed by using the statistical energy analysis (SEA). Full frequency underwater radiated noise prediction of the oil tanker was completed. In the end, the far field of ship underwater sound radiation was studied. The far field can be determined when the sound radiation directivity of the ship no longer changes with distance.