Finite amplitude acoustic propagation modeling using the extended angular spectrum method

The angular spectrum method is a technique for modeling the propagation of acoustic fields between parallel planes. The technique may be used to predict an acoustic pressure field distribution over a plane, based upon a known pressure field contour at a parallel plane. In addition to the modeling of diffractive phenomena, the technique has been extended to include the effects of attenuation, dispersion, refraction, and phase distortion. Recently, the ability to predict the effects of finite amplitude propagation through nonlinear media has also been incorporated into the model. This paper focuses on the incorporation of the latter effect. The motivation behind this research and the theory upon which the model is based are summarized, and comparisons between experimental data and extended angular spectrum predictions are presented.