Sound Power Measurement For Underwater Moving Sound Source Based On Scaling Of Sound Intensity

The radiated sound power of a sound source can quantitatively reflect the intensity and properties of noise,and is one of the parameters that can best characterize the characteristics of sound radiation.Accurate measurement of the radiated sound power of the sound field of complex structures such as underwater vehicles is a key link in vibration and noise reduction,which is helpful for the formulation of noise reduction schemes.Most of the traditional measurement methods and standards are aimed at static sound sources.For moving sound sources,the measurement is more complicated and difficult,which is the focus of attention in underwater acoustic work.At present,the commonly used method of measuring the radiated sound power of moving sound source needs to place a large number of measuring points around the sound source to make each measuring point move synchronously with the measured sound source,so as to eliminate Doppler effect,convert the sound pressure of each measuring point into sound intensity,and integrate to obtain sound power.However,this method is limited in practical application.When the volume of the sound source is large and the motion speed is fast,the measurement arrangement becomes more difficult.Moreover,the test time of this method is usually long,and the measurement value of the instantaneous sound power of the unsteady sound source cannot be obtained.Therefore,the study of a radiation noise measurement method for underwater moving sound source has a certain theoretical value and practical significance for improving the accuracy of underwater vehicle sound field measurement.In this paper,aiming at the problem of measuring radiated sound power of underwater moving sound source,a method of measuring radiated noise of underwater moving sound source based on beamforming scaling sound intensity technology with dynamic changing integral range is proposed.The underwater target sound source is located by using the timedomain beamforming method to remove Doppler effect,and then the sound field information is extracted.The sound intensity scaling method is used to combine the beamforming output of the microphone array with the radiated sound power of the sound source,so that the sound pressure obtained from the measured array is converted into its corresponding sound intensity,and the result is carried out by plane integration.The radiated sound power of the sound source is estimated.In this paper,the numerical simulation of single point moving sound source and combination moving sound source is carried out respectively,and the influence of measurement array,virtual plane size and distance between source plane and array on the measurement sound power is analyzed.In addition,the partition method of virtual plane and global plane is proposed for combination sound source,and the optimal parameters are determined.At the same time,a model of underwater structure is constructed,and the optimal parameters are used to measure the radiated sound field of the structure,which expands the application range of the zooming sound intensity method.Finally,the experimental results show that the measurement method of underwater moving sound source radiation noise based on zooming sound intensity with dynamic change integral range can realize the effective measurement of underwater moving sound source sound field,which has certain feasibility and application prospect.