Development of a Parabolic Approximation for the Computation of Propagation Loss in a Range-Dependent Environment
We propose to solve the Helmholtz equation by means of the parabolic approximation in a two-dimensional environmental propagation. We make clear the solution for a quadratic development of the propagation operator which allows us to take into account a larger angular aperture of the source. The numerical solution is given by an algorithm of finite differences using the Crank-Nicholson method. The problem of rectilinear, horizontal and oblique interfaces between two fluid media is solved. The problem of the medium where the sound velocity profile changes with range is treated by conditions of continuity between two media with the given sound speed profiles. The first results of numerical simulations executed on the VAX 11/780 and the array processor FPS 164 are presented. They show the ability of the model to describe the importance of environmental variation on propagation.
KeywordsHelmholtz Equation Mesh Point Sound Field Source Depth Paraxial Approximation
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- 1.F.D. Tappert, The parabolic approximation method. In: J.B. Keller and J.S. Papadakis, eds. Wave propagation and underwater acoustic. Springer, Berlin, 1977.Google Scholar
- 5.D.J. Thomson and N.R. Chapman, A wide-angle split-step algorithm for the parabolic equation, J. Acoust. Soc. Amer. 74, 1848–1854.Google Scholar
- 6.B. Grandvuillemin, Application de l’approximation parabolique a l’acoustique sous-marine. These de 3eme cycle. Spécialité en acoustique. Université d’Aix, Marseille II (1985), France. 795–800.Google Scholar