Efficient computation of sound field above ground in horizontally stratified media using a Wentzel–Kramers–Brillouin-type approximation with Airy functions

Abstract

Conventional fast field programs model a general refractive index profile with a system of horizontal layers. The choice of layer thickness and number of layers depends on frequency, range, and intrinsic properties of the refractive index profile. These constraints result in excessive computation time for many practical cases. To avoid the long run times associated with the layered model, a Wentzel–Kramers–Brillouin-type (WKB) approximation with Airy functions has been applied to the efficient computation of the height-dependent acoustic pressure. Numerical results demonstrate that the new fast field program can reduce the computer time about 50-fold. For higher frequencies, the new fast field program can save more computer time.