ASA 125th Meeting Ottawa 1993 May

5aPA6. A numerical study of sound propagation through a turbulent atmosphere.

Daniel Juve

Philippe Blanc-Benon

Patrick Chevret

Dept. of Acoust., Ecole Centrale de Lyon, 36 Av. Guy de Collongue, 69131 Ecully Cedex, France

A numerical simulation of the effect of turbulent conditions on the propagation of acoustic waves in the atmosphere has been developed. The turbulence is represented as a set of realizations of a random field generated by a limited number of random Fourier modes [Karweit et al., J. Acoust. Soc. Am. 89, 52--62 (1991)]. Through each individual realization, the acoustic pressure field is computed in the parabolic approximation. Ensemble averaging is thus performed to obtain the statistical properties of the field: mean level, standard deviation of the fluctuations, probability density functions, etc. Results will be given in particular for upward refracting conditions, when turbulence diffracts sound into the deterministic shadow zone.