AN IMPROVED RAY-TRACING ALGORITHM FOR PREDICTING SOUND-PROPAGATION OUTDOORS

A new ray-tracing method for predicting the sound field near a flat im pedance ground in a refracting atmosphere is developed that includes t he effect of vector wind and turbulence explicitly. Improvements on pr evious ray-tracing schemes include the use of a generalized Snell's la w, an integration by means of a Gaussian quadrature, and a bracketing method for finding the ray paths. For the turbulence calculations, the interray coherence is determined from turning point heights rather th an from integrals along the ray paths. A more efficient algorithm is d eveloped for computing the sound field above an impedance plane in a r ealistic atmosphere. Despite the inherent limitations of the ray-trace approach, particularly in respect of logarithmic wind profiles, the a lgorithm is valid over a wide range of practical situations. (C) 1998 Acoustical Society of America. [S0001-4966(98)04010-7]