Fluctuations of spherical waves in a turbulent atmosphere: Effect of the axisymmetric approximation in computational methods
article
The validity of the axisymmetric parabolic-equation (PE) method for line-of-sight sound propagation in a turbulent atmosphere is investigated. The axisymmetric PE method is a finite-difference method for solving a 2D parabolic wave equation, which follows from the 3D wave equation by the assumption of axial symmetry around the vertical axis through the source. It is found that this axisymmetric approximation has a considerable spurious effect on the fluctuations of the sound field. This is concluded from analytical expressions for the log-amplitude and phase variances, derived both for isotropic turbulence and for axisymmetric turbulence. The expressions for axisymmetric turbulence are compared with the results of numerical computations with the PE method. (C) 2000 Acoustical Society of America.
Topics
TNO Identifier
235712
ISSN
0001-4966
Source
Journal of the Acoustical Society of America, 108(4), pp. 1528-1534.
Pages
1528-1534
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