A marching-frame, finite-element, range-dependent, ocean acoustic propagation and scattering model for long-range acoustic propagation simulation

Abstract

The ocean acoustic propagation and scattering simulation model based on the finite-element method [J. E. Murphy and S. A. Chin-Bing, Math. Comput. Modeling 11, 70–74 (1988)] has been extended to long ranges using a marching-frame approach. This F_inite-element, F_ull-wave R_ange-dependent, A_coustic M_arching E_lement (FFRAME) model has the advantage of a forward marching model (similar to the marching algorithms of parabolic equation models) while allowing that within each elemental frame the computed pressure field is full wave and range dependent. Successive flames are coupled by imposing the pressures from the right-hand side of the Nth frame onto the corresponding nodes on the left-hand side of the (N + 1)th frame. The size of each elemental frame can be adjusted to include all of the significant effects due to full-wave propagation and scattering within that frame. Thus the forward propagating field between elemental frames correctly includes the losses due to backscatter. Numerical examples are presented that illustrate the advantage of the FFRAME model over conventional one-way ocean acoustic propagation models. [Work supported by ONR and NORDA.]