Research On The Prediction And Control Of Ship Cabin Noise Under The Influence Of Bow Thruster

With the higher and higher demand on ship noise International Maritime requires,shipyard,design institutes and research departments begin to carry out noise prediction of new ships to realize more rational ship low-noise design.Due to the increasing number of offshore platforms in recent years,the requirements of the PSV(Platform Support Vessel)which provide services for offshore platforms have been increasing.As a special ship,PSV not only need to operate in the sailing condition,but also need long-term operation in the dynamic positioning condition.At this time,for the PSV whose superstructure cabins located above the bow thruster,compared with the propulsion propeller and other mechanical equipment,bow thruster is the main cause of excessive ship noise.For the noise problem of ship cabin caused by bow thruster,this paper introduces the composition,classification and working principle of bow thruster,and analyzes its noise characteristics and influence factors.In VA One,the statistical energy model and the finite element model of the 85 m PSV are established.After finding out the excitation source of the ship,the noise of each ship cabin in the high frequency(63Hz ~ 8000Hz)is predicted under the condition of the thruster propeller with cavitation and without cavitation.It is verified that the noise of the platform is influenced mainly by thruster propeller.The prediction of the cabin noise is consistent with the measured value by comparing the measured value with zero-pitch and 40%-pitch value.Noise propagation law of ship cabins is analyzed.The effect of outboard water and stiffened plates on cabin noise is studied,and the low frequency noise prediction in the finite element method in VA One is discussed.For the ship cabins exceeding seriously in PSV,the structure of the box “box” is introduced and the actual verification is carried on in the model.The new type composite floor PK-90 STEEL + LITOSILO is analyzed from structural form and noise reduction characteristics,and its noise reduction effect is verified in VA One.At last,this paper considers low noise design from the bow thruster.The purpose of this paper is to forecast the cabin noise during the dynamic positioning condition of PSV by numerical calculation,analyze the noise propagation law under the dynamic positioning condition,achieve the purpose of reducing noise through the design of the structure and bow thruster and provide design guidance for the construction of new ships.