Research On The Method Of Noise Source Location In Closed Space Based On Cylindrical Array

The location of noise source is a prerequisite for effectively control noise.In the field of noise source location,near-field acoustic holography and beamforming technology are widely used.Near-field acoustic holography has a good resolution in the low frequency band,but it is necessary to increase the number of array elements to ensure its location ability in the high frequency band.Comparing with the near-field acoustic holography,the beamforming can achieve better location effect with less array elements in the high frequency band,but its resolution is low in the low frequency band.And these methods are based on two-dimensional array such as a planar array,which is not suitable for the noise source localization in the entire three-dimensional space.Comparing with the planar array,the cylindrical array can record more comprehensive three-dimensional sound field information.It has advantages in the field of noise source localization.The most study of near-field acoustic holography and beamforming technology is based on free field space.The localization performance of these methods will be significantly reduced in enclosed space such as aircraft,automobile,and ship cabin.Therefore,in this paper,the method of sound field separation and sound intensity focused beamforming is studied to improve the performance of noise source localization in enclosed space.The combined method of cylindrical near-field acoustic holography and focused beamforming based on the cylindrical array is used to locate the noise source in enclosed space.Firstly,this paper introduces the principle of cylindrical near-field acoustic holography and acoustic field separation.The reception data model of near-field cylindrical array is established and the basic theory of sound intensity focused beamforming is introduced.Then,the location performance of the acoustic holography and focused beamforming is simulated and analyzed.Considering the practicality of the project,the influence of the incomplete cylindrical array on the location performance is analyzed.The spatial resolution of the two techniques is discussed to divide the effective frequency band of noise source location.Considering the actual sound field distribution in the enclosed space,using COMSOL software to simulate the sound field distribution in enclosed space,the sound pressure data measured by double layer cylindrical array in enclosed space are extracted.The cylindrical near-field acoustic holography technique is used to locate the noise source in the low frequency band,and the intensity focused beamforming technique is used in the high frequency band.The influence of various parameters of the cylindrical array on the locationperformance is discussed.The double-layer cylindrical scanning array is designed and processed.The noise source location test was carried out in the enclosed cabin model utilizing the array to verify the method effectiveness in the location of the noise source in the enclosed space.Finally,the software of the cylindrical array noise source localization with simulation and experimental data processing is designed,and the operating interface is designed.The result shows that the near-field acoustic holography has a better location performance for the noise source with low frequency in the enclosed space,and the intensity focused beamforming has better location performance in the high frequency band.The combination of two methods is overcome the shortcomings of the location performance of near-field acoustic holography is poor in the high frequency band and the location accuracy of focused beamforming is not high in the low frequency band.The method realizes the noise source location in the wide frequency band,near field and far field location under the closed space condition.