Research On Influence Of The Size Of Non-anechoic Water Tank On Vibration And Radiation Characteristics Of Cylindrical Shell

At present,the radiation noise measurement of large water equipment is mostly in the field,but the number of field test sites is limited,and the measurement cost is high,which requires a lot of manpower and material resources.Compared with the field,the non-anechoic pool can largely compensate for the shortcomings of the field and facilitate the test.However,when large equipment is placed in the non-anechoic tank,to what extent the proportion of equipment size and non-anechoic tank size will affect the measurement,which is a problem that needs to be considered.Based on the above problems,the research work of this paper is to study and experimentally verify the influence of non-anechoic tank size on the surface vibration of cylindrical shell model,and to conduct acoustic measurement of the characteristics of cylindrical shell model radiated outward when excited vibration occurs in non-anechoic tank.The main differences between the non-anechoic tank and the anechoic tank are reflected in the boundary conditions and the acoustic field mode.Therefore,this paper focuses on the influence of the non-anechoic tank scale and the acoustic field mode in the tank on the acoustic vibration characteristics of the cylindrical shell model.The numerical simulation studies the acoustic vibration characteristics of the cylindrical shell model in a variety of closed spaces and free fields with different sizes,and studies and analyzes them from the perspectives of vibration,radiation acoustic power and radiation impedance.The results show that when the cylindrical shell model is arranged in the geometric center of the non-anechoic flume,with the increase of the volume proportion of the cylindrical shell in the closed space,the amplitude of the resonant peak changes more and more,the number of the affected resonant peaks will increase,and the frequency offset corresponding to the resonant peak will also increase.The cylindrical shell model is arranged at the geometric center of the same closed space.Under the same volume ratio,the influence of radiation acoustic power is greater than that of vibration.The difference of radiation acoustic power level in unit bandwidth is approximately twice the difference of vibration velocity level.The boundary with large impedance has greater influence on the vibration of cylindrical shell than the boundary with small impedance.The surface vibration and radiated sound power of cylindrical shell model were measured in non-anechoic tank and anechoic tank.The excited vibration and radiated acoustic power data of the cylindrical shell model are measured,and the radiation impedance data of the shell are calculated.The experimental results show that the variation law of the excited vibration of the cylindrical shell model in the non-anechoic tank is basically consistent with the simulation results.