ASA 125th Meeting Ottawa 1993 May

5aPA5. A fast phase-screen method for sound propagation through a turbulent atmosphere.

Xiao Di

Natl. Ctr. for Phys. Acoust., Univ. of Mississippi, University, MS 38677

Inst. for Microstruct. Sci., Natl. Res. Council, Ottawa, ON K1A 0R6, Canada

Kenneth E. Gilbert

Lucy J. Ameling

Penn State Univ., State College, PA 16804

An ``integrated-turbulence'' phase screen method has been developed to efficiently treat sound propagation through turbulence having both small-scale and large-scale structure [X. Di and K. E. Gilbert, J. Acoust. Soc. Am. 92, 2404 (A) (1992)]. In this paper, the method is used with two different parabolic equation (PE) algorithms: a PE based on a Fourier transform, split-step range step and a PE based on a Crank--Nicolson range step. It is shown that the phase-screen approach allows one to take advantage of the much longer range step possible with the Fourier method and thereby speed up the calculation by a factor of approximately 100 relative to the Crank--Nicolson result. Consequently, with the phase-screen method and the Fourier PE, it is practical to directly compute the statistics of the fluctuations in the acoustic field. Results are shown from such calculations and comparisons are made with available experimental results.