Application of the angular spectrum approach to compute the far-field pressure

Abstract

The angular spectrum decomposition of an acoustic source can be used to compute the radiation pressure in three dimensional radiation problems. Then, the aim of this paper is to demonstrate that the discrete far-field pressure can be computed from the two-dimensional (2D) discrete Fourier transform (DFT) of the normal velocity. In fact, using the asymptotic expression of the Rayleigh integral, it will be shown that the analytical far-field pressure is given by the 2D Fourier transform of the normal velocity. Using the discrete form of this expression, guidelines for selection of the sampling interval and the size of baffle in which the source is mounted will be given. The case of a rectangular source mounted in a rigid baffle and radiating into water will be considered.