標題: On optimal retreat distance of equivalent source method-based near-field acoustical holography
作者: Bai, Mingsian R.
Lin, Jia-Hong
Chen, Ching-Cheng
機械工程學系
Department of Mechanical Engineering
公開日期: 2010
摘要: This paper presents two nearfield acoustical holography (NAH) approaches using Equivalent Source Methods (ESM). The indirect ESM is derived from discretizing the simple layer potential integral, while the direct ESM is derived from discretizing the Helmholtz Integral Equation (HIE). In the indirect ESM, sound field is represented by a distribution of monopoles. In the direct ESM, on the other hand, sound field is represented by monopoles and dipoles. In the ESM formulation, it is vital that the virtual sources "retreat" from the reconstruction surface to avoid singularity. However, the distance can not be increased without limit because of the ill-posedness inherent at large reconstruction distance. It is widely believed that the retreat distance of one to two lattice spacing is appropriate. This paper revisits this issue of retreat distance, with the aid of an optimization technique: the golden ratio search with parabolic interpolation. Simulations are conducted for baffled planar and spherical pistons. The simulation results reveal that, differing from the widely accepted value, the retreat distance appropriate for the ESM is half of lattice spacing.
URI: http://hdl.handle.net/11536/135593
期刊: PROCEEDINGS OF THE 17TH INTERNATIONAL CONGRESS ON SOUND AND VIBRATION
顯示於類別:會議論文