ASA 124th Meeting New Orleans 1992 October

5aUW7. Application of finite-element models to backscatter from shallow water internal waves.

Stanley A. Chin-Bing

David B. King

Naval Res. Lab. Det., Code 7181, Stennis Space Center, MS 39529

Joseph E. Murphy

Gongqin Li

Dept. of Phys., Univ. of New Orleans, New Orleans, LA 70148

The acoustics effects of shallow-water, solitary, internal-wave packets (solitons) have been simulated using finite-element computer models (foam, fframe, and safe). The coupled effects of the total shallow-water waveguide with its range-dependent boundaries and penetrable, shear-supporting ocean-bottom properties were included in the simulations. Our previous numerical studies at 75 Hz (and lower) had shown recognizable, although extremely weak, backscatter from the solitons with the influence of shear waves being significant only in the forward propagation. If combined effects of backscatter and shear wave conversion are significant, it is likely at higher frequencies. Examples at higher frequencies (100--250 Hz) that investigate backscatter from solitons and its possible conversion into ocean-bottom shear waves will be presented. [Work supported by ONR/NRL and ONR Acoustic Reverberation SRP.]