Research On The Prediction Of Underwater Acoustic For A Survey Ship And Reduction For Its Noise And Vibration

With the growth in demand for marine resources which used for offshore oil, marine environment, marine life and seabed topography measurement, various survey ships are paied so much attention recent years. The vibration and noise of the survey ship need strict control because it need the help of acoustic equipment to detect marine resources, as a result, higher standards for the vibration and noise reduction of ship design are proposed. For high-performance survey ship, in the design stage, the prediction for vibration and noise are needed in order to improve the ship structure, make assessment and decisions on the ship vibration and noise reduction design.A survey ship was taken as the research object. The harmonic response analyses of its main acoustic and vibration source had been taken out by means of the FEM software. Underwater acoustic forecast in low frequency band was carried out combined with acoustic BEM software. The research and prediction of underwater acoustic radiation characteristics in mid and high frequency band were conducted by using SEA. On this basis, the methods to control ship structure vibration and reduce underwater acoustic were researched, and in accordance with engineering requirements, the software secondary development has been made on the harmonic response analyses.This article includes the following aspects: First, a survey ship finite element model was established with the finite element software, the inherent characteristics of the hull was got based on modal analysis, then the harmonic response analyses of its main vibration source had been taken out by means of the FEM . Second, study on the dynamics vibration and underwater sound radiation characteristics on the flow-structure interaction model of the underwater shell structure with FEM combined with BEM, and research on the methods to reduce underwater acoustic. Third, research and prediction of underwater acoustic radiation characteristics in mid and high frequency band were conducted by using statistical energy analysis on the statistical energy model of the survey ship. Fourth, based on the PCL, the software secondary development has been made on the harmonic response analyses of its main load and underwater radiated noise forecast at low frequency.