### ASA 124th Meeting New Orleans 1992 October

## 3aUW10. Mean energy calculations in a numerical parabolic equation average
propagation method.

**Roger M. Oba
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*Naval Res. Lab., Stennis Space Center, MS 39529-5004
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A computational method of numerically computing average pressure has been
developed using a normal mode analysis of the parabolic equation [R. M. Oba, J.
Acoust. Soc. Am. 91, 2424 (A) (1992)]. It has been implemented to compute the
transmission loss and phase for the average solutions in the continuous wave
case. Time domain cases have been computed by Fourier transform. This analysis
can be extended to compute the average energy over the ensemble at a given
range in the continuous wave case. Since energy is positive for each element of
the ensemble, the calculation of its mean will obviate the larger transmission
loss due to phase cancellation in ensemble averaging of the complex valued
solutions. Comparison of average energy calculations can be made to the energy
of the average solution. This technique will be useful in matching this
computed field at some final range to another solution starting from that range
on. [Work supported by ONR/NRL-SSC and ONR Young Navy Scientist Program.]