GEOMETRICAL ACOUSTICS' THEORY OF WAVES FROM A POINT SOURCE IN A TEMPERATURE-AND WIND-STRATIFIED ATMOSPHERE.
Interim scientific rept.
AVCO CORP WILMINGTON MASS AVCO SPACE SYSTEMS DIV
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This paper is concerned with the propagation of acoustic waves in temperature-and wind-stratified atmospheres in the geometrical acoustics approximation. The basic theory of Blokhintzev is shown to hold for propagation in the atmosphere, even when gravitational forces and pressure gradients are included, if wave periods are sufficiently short. The ray-tracing equations are derived from the eikonal approximation using Cauchys method of characteristics, and the boundary conditions on these equations appropriate to a point source are discussed. Previous approximate methods of integrating the ray-tracing equations with the neglect of cross-winds are discussed, and a formulation due to Lee is corrected. A numerical method is introduced which alloys cross-winds to be taken into account. An extension of this method, to include earth curvature effects, is also included. Author