The Application Research On Green's Functions In Planar Near-field Acoustic Holography

As more popular sound field visualization technique in recent years Near-field acoustical holography technology can effectively carry out the reconstruction of the sound source, and has good maneuverability and engineering realizability. Planar near-field acoustic holography is near-field acoustic holography based on the plane boundary condition. Green's function as a space transmission factor, indicating the relationship of the sound source and the sound field, the nature and state of Green's function has a decisive role for the accuracy and reliability of the near-field acoustic holography reconstruction which has the ill-posed problem.The planar near-field acoustic holography is studied in this paper based on Green's Functions, which is discussed the finite discrete Green's function methods in the Dirichlet and Neumann boundary conditions. Analyze the characteristic of Green's functions with different finite discrete forms and the impact of Green's functions with different reconstruction parameters. Through the simulation of two-point sources, analyze the impact on accuracy and resolution when the sound field carries out forward and reverse reconstruction with different finite discrete Green's function forms. Two reconstruction algorithms and the corresponding Green's Functions are compared, one of which is based on the measured sound pressure and the other on the measured particle velocity. Finally, the article analyses the experiment results based on the sound pressure reconstruction and particle velocity experiments reconstruction.Through the simulation and calculation, it can be seen that K-space Green's function method is only applicable with the near-field reconstruction, and it can receive a good resolution in the near-field reconstruction. Real-space Green's function method has less sensitive than K - space Green function method for the reconstruction distance. The experimental results indicates that the excellence and disadvantage of the sound pressure reconstruction based on the Dirichlet boundary condition and the sound pressure reconstruction based on the Neumann boundary condition .