Research On Noise Environment Characteristics Of Small Waterplane Area Twin Hull

Noise environment of the ship includes superstructure cabin noise, underwater radiation noise and the self-noise, which has huge impact both on the staff and equipments on board, besides the safety of the ship itself, and must be controlled. However, no matter what measures in vibration and noise reduction was taken after the ship built completely, in general it can only solve partial problems with a great cost. Therefore the accurate prediction of ship noise during the ship design stage has a very important practical significance.Compared with the traditional monohull ship, SWATH has great distinction in the body structure, layout features, power equipment and other aspects, thus its noise environment such as underwater radiated noise, sonar self-noise and superstructures cabin noise is different from traditional monohull ship,. In this paper, a major noise environment prediction was made to the SWATH. Statistical energy analysis (SEA) was used to analyze superstructure cabin noise of SWATH, and the effect of superstructure typical cabin noise from outfitting materials was studied. To those cabins which noise still can not meet the specifications after considering outfitting materials, the noise transfer characteristics were analyzed to study the noise transmission channels. Then after obtaining the dominant pathway of cabin noise, appropriate measures were taken to reduce vibration and noise to make cabin noise meet the specifications.Both the SEA and FEM/BEM were used to analyze the three main underwater radiation noise components:mechanical noise, propeller noise and hydrodynamic noise, of SWATH. SEA was used to analyze the high frequency underwater radiated noise and finite element/ boundary element coupling method was used to analyze the low frequency underwater radiation noise. The noise contribution in the amount of three main components to SWATH on underwater radiation noise under different speed was obtained.To the high-frequency characteristics of the sonar transducer cabin, the SEA and BEM were used to analyze the three main noise components of the sonar transducer cabin which are mechanical noise, propeller noise and high frequency hydrodynamic noise. The noise contribution in the amount of three main components to the sonar transducer cabin on underwater radiation noise under different speed can be obtained.