### ASA 125th Meeting Ottawa 1993 May

## 5pUW2. Sound-pressure level calculations using the RRA algorithm for
depth-dependent speeds of sound valid at turning points and focal points.

**Lawrence J. Ziomek
**

**
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*Dept. of Electr. and Computer Eng., Code EC/Zm, Naval Postgrad. School,
Monterey, CA 93943
*

*
*
Sound-pressure level (SPL) calculations are made along individual ray
paths for one-dimensional, depth-dependent, speeds of sound using an enhanced
version of the recursive ray acoustics (RRA) algorithm. The SPL calculations
are valid (i.e., finite) at turning points and focal points and do not require
the use of Airy functions. The SPL calculations include the effects of
frequency-dependent volume attenuation and frequency-dependent attenuation due
to surface and bottom reflections. The ocean surface and bottom are treated as
boundaries between viscous fluid media. Although the ocean surface is modeled
as a planar boundary, the bathymetry is an arbitrary function of horizontal
range. Sound speed versus depth and bathymetric data are represented by
orthogonal function expansions. Computer simulation results from preliminary
test cases are presented. [Work supported by NAVSEA.]