ASA 127th Meeting M.I.T. 1994 June 6-10

3aUW1. Acoustic propagation in waveguides of variable thickness.

R. A. Coury

W. L. Siegmann

Rensselaer Polytech. Inst., Troy, NY 12180-3590

Michael D. Collins

Naval Res. Lab., Washington, DC 20375

The parabolic equation (PE) method is an efficient approach for solving range-dependent ocean acoustics problems. Many types of range dependence have been considered previously, including variable sound speed, ocean depth, density, and other sediment parameters. Recently, interest has increased in problems involving waveguides with variable depths, for example, the case of a sloping ocean bottom that continues onto a beach. A new PE that allows for variations in the size of the waveguide has been formulated using energy conserving techniques. In addition, environments where this PE has validity are identified and discussed. Numerical results obtained using the new PE will be presented. [Work supported by ONR.]