Closed Spatial Noise Source Location Based On Spherical Array

The noise source localization is a necessary prerequisite for noise control.The spherical array has the omnidirectional and three-dimensional symmetry of latitude and longitude.Its special structure makes it have great flexibility and can measure the sound field information of the whole three-dimensional space.It has unique advantages on the noise source positioning in the Aircraft,cars and rooms and other enclosed space.Near-field acoustic holography has better spatial resolution in the low-frequency rigion,but the microphones numbers should be increased to guarantee its localization performance in the high frequency range.In the high frequency range,near-field beam forming can achieve better localization accuracy with fewer microphones than near-field acoustic holography,but its spatial resolution is low in the low frequency range.In this paper,the method of identifying noise sources combined these two algorithms were studied,The frequency band of the two algorithms is divided,and the performance of the algorithm Simulation analysis is carried out.A transfer matrix from spherical to cylindrical is constructed to deal with the problem of location identification of sound sources in a closed columnar sound source and a cylindrical column.The sound field distribution in the closed space is simulated with COMSOL,at low frequency region,the sound field is reconstructed by the SNAH,which achieve the noise source localization in the closed space,at high frequency range,The focused beam forming is used to realize the noise source localization.A 64-element spherical microphone array with randomly distributed array element was designed and processed.The noise source localization experiment was carried out in the free-field and closed-chamber model based on the spherical array.The experimental data were processed by two algorithms.Finally,a software for source localization of closed-space noise based on spherical array is designed,which contains the algorithm simulation and experimental data processing.The results show that the spherical arrays have full spatial stable target localization performance.The SNAH has high localization accuracy for the low-frequency sound sources in the closed space,and in the high-frequency long-distance field,the focused beam forming has high sound sources localization accuracy.The two methods are combined to locate the wide frequency range sound sources with smaller spherical array and less array element.