Barry J. Doust
Applied Research Laboratory and the Graduate Program
in Acoustics, Pennsylvania State University, P.O. Box 30, State
College, PA 16804
The advancement of the Parabolic Equation (PE) for use in solving
ocean acoustic propagation problems has increased steadily over
the past decade. A major result of these advancements has been
to eliminate or reduce some of the primary limitations originally
associated with the PE. The following presents a model utilizing
a method developed by Hardin and Tappert whose PE was the first
PE to be implemented in underwater acoustics. This method, the
"Split-Step" method, makes use of Fourier Transforms
to implement a range-marching technique. The simplicity of the
technique presents itself as an initial value problem in range
requiring only a defined source over depth at initial range. Matlab
code is produced to evaluate transmission loss for a few simple
cases of environmental variation. Computational efficiency restricts
the examples to low frequencies while the translation of the code
to FORTRAN along with some additional optimization will improve
efficiency for higher frequencies and larger domains. The results
are shown for two profiles with a 10 Hz source located 500 meters
below the surface. The visualization shows some features of a
properly conditioned model with further optimization required
to evaluate more complicated domains.
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