Abstract:

A finite length ping ray trace program (FLPRT) has been extended which is now capable of simulating time-dependent wave motion in a complicated elastic bathymetric waveguide. From the original concept of sound waves being generated from an infinite set of point sources, FLPRT expands a finite set into the following ray theory including shear and compression logic in a half-space. Wave propagation is demonstrated in a constant velocity shallow-ocean environment for both flat and sloping bathymetries. Not only is the objective to compare the model-generated transmission loss calculations against those computed by EFEPE, an elastic parabolic equation model by Collins of ARL, but also show the time-generated path of the acoustic waves in both cases. Narrow angle-generated pings show nonmodal characteristics than those generated by wide-angle pulses which exhibit fluctuating waves predicted by normal mode theory. As in all cases, adiabaticity is assumed within each very small incremental time step. A 3- to 5-min videotape will be shown on a VCR demonstrating wave motion in the presence of a flat and sloping wedge half-space exhibiting both shear and compressional waves on the half-spaces.