ANALYTICAL SOLUTIONS FOR OUTDOOR SOUND-PROPAGATION IN THE PRESENCE OFWIND

A theoretical analysis for the sound field due to a point monopole sou rce in a fluid, layered atmospheric environment is described. The anal ysis has included explicitly the effect of fluid motion in the three-d imensional wave equation. The atmospheric environment is assumed to ha ve sound-speed and vector wind-velocity profiles that either increase or decrease monotonically with height. In addition, the atmosphere is assumed to be vertically stratified. In such an environment, the solut ion can be expressed analytically in terms of Airy functions but the f orms of solution are different for the situations of upward and downwa rd refraction. Some sound-speed and wind-velocity profiles are amenabl e to exact analyses. Two notable examples are (i) a windless environme nt with a linear sound-speed profile; and (ii) a medium with a linear wind shear layer and a constant sound speed. These two profiles are st udied analytically and compared numerically with other computational s chemes. The validity of a heuristic approximation, which replaces the vector wind-velocity profile with an effective sound-speed profile, is also investigated numerically. (C) 1997 Acoustical Society of America . [S0001-4966(97)05309-5] PACS numbers: 43.28.Fp, 43.20.Bi [LCS].