Research On Sound Field Reconstruction Technology Of Underwater Sound Source Based On Near Field Acoustic Holography

Near-field acoustic holography is a technology which can identify the sound source and visualize the sound field visualization.In this paper,the planar near-field acoustic holography based on spatial sound field transformation was studied,which provides an effective method for the identification of noise sources and the measurement of far-field characteristics of high-frequency underwater acoustic transducers.Furthermore,the theoretical analysis and formula derivation of near-field acoustic holography were carried out,besides,the acoustic holographic formula was also discretized.When the inverse reconstruction of sound field was carried out,the selection of filter window function was discussed.The related parameters affected the accuracy of acoustic holography were studied.The feasibility analysis of the positive sound field reconstruction of the rectangular piston transducer array is carried out,combined with the two-dimensional plane sound pressure construction technology,the measurement efficiency can be greatly improved;The simulation calculation and experiment results show that the near-field acoustic holography algorithm can effectively calculate the sound field information of the prediction surface and control the reconstruction error within 10%.Then,the sound field prediction analysis of the circular piston transducer was carried out,the simulation calculation and experimental results show that the reconstruction error increases with the increase of the reconstruction distance.The reconstruction error can be effectively reduced by setting the relevant parameters reasonably.Based on the basic theory of near-field acoustic holography,based on the Green's function and its angular spectrum under two kinds of boundary conditions,the reconstruction accuracy and sensitivity of edge error based on sound pressure reconstruction and particle-based vibration velocity reconstruction are compared by simulation.The cylindrical near-transistor is used as the experimental object to study the near-field acoustic holography in water.The experiment results show that the sound field reconstruction of particle velocity can reflect the sound source position and relative size more accurate than the sound pressure based sound field reconstruction,which also verifies the effectiveness and accuracy of near-field acoustic holography in sound field reconstruction and visualization.