Abstract:
The scattering cross section, (sigma), and the variances of log-amplitude and phase fluctuations, <(chi)[sup 2]> and <(phi)[sup 2]>, of a sound wave propagating in a moving random medium (turbulent atmosphere or ocean, etc.) with the von Karman spectra of temperature and medium velocity fluctuations are calculated. The derived equation for (sigma) differs from that obtained in the paper [Baikalova et al., J. Acoust. Soc. Am. 83, 1332--1335 (1988)]. The difference is due to the fact that in this paper the von Karman spectra of temperature and medium velocity fluctuations are assumed to have the same form, while it is known in the theory of turbulence that these spectra have different forms [J. Hinze, Turbulence (McGraw-Hill, New York, 1975)]. The derived equations for <(chi)[sup 2]> and <(phi)[sup 2]> are new results. It is shown that <(chi)[sup 2]> and <(phi)[sup 2]> depend on the wave parameter D, widely used in the theory of waves in random media. For D<<1 and D>>1, <(chi)[sup 2]> and <(phi)[sup 2]> coincide with the values previously calculated for the cases of sound propagation in media with the Kolmogorov and Gaussian spectra of temperature and medium velocity fluctuations. [This material is based upon work supported by the U.S. Army Research Office under Contract No. DAAH04-95-1-0593.]