An explicit analytical solution for sound propagation in a three-dimensional penetrable wedge with small apex angle.

A problem of sound propagation in a shallow-water waveguide with a weakly sloping penetrable bottom is considered. The adiabatic mode parabolic equations are used to approximate the solution of the three-dimensional (3D) Helmholtz equation by modal decomposition of the acoustic pressure field. The mode amplitudes satisfy parabolic equations that admit analytical solutions in the special case of the 3D wedge.

Leading-order cross term correction of three-dimensional parabolic equation models.

The issue of handling a leading-order cross-multiplied term in three-dimensional (3D) parabolic equation (PE) based models is addressed. In particular, numerical results obtained incorporating a leading-order cross-term correction in an existing 3D PE model, written in cylindrical coordinates, based on higher-order Padé approximations in both depth and azimuth, and a splitting operator technique are reported. Note that the numerical algorithm proposed in this paper could be used in the future to update any 3D PE codes that neglect cross terms and use a splitting numerical technique.

Comparisons of laboratory scale measurements of three-dimensional acoustic propagation with solutions by a parabolic equation model.

In this paper, laboratory scale measurements of long range across-slope acoustic propagation in a three-dimensional (3-D) wedge-like environment are compared to numerical solutions. In a previous work, it was shown that the experimental data contain strong 3-D effects like mode shadow zones and multiple mode arrivals, in qualitative agreement with theoretical and numerical predictions. In the present work, the experimental data are compared with numerical solutions obtained using a fully 3-D parabolic equation based model.

Scaled model experiment of long-range across-slope pulse propagation in a penetrable wedge.

In this paper, laboratory scale measurements of long-range across-slope propagation of broadband pulses in a shallow-water wedge-shaped environment with a sandy bottom are reported. The scaled model was designed to study the three-dimensional (3D) acoustic field in the presence of only a few propagating modes. The recorded time series exhibit prominent 3D effects such as mode shadow zones and multiple mode arrivals.

Numerical investigation of out-of-plane sound propagation in a shallow water experiment.

In an experiment in the Florida Straits, broadband pulses were transmitted over a range of 10 km and received by a vertical hydrophone array. For pulses with center frequency below 400 Hz, the received signal consisted of a dominant arrival followed by a secondary one delayed by about 0.4 s.

On the use of higher-order azimuthal schemes in 3-D PE modeling.

In this paper, the issue of using higher-order finite difference schemes to handle the azimuthal derivative term in a three-dimensional parabolic equation based model is addressed. The three-dimensional penetrable wedge benchmark problem is chosen to illustrate the accuracy and efficiency of the proposed schemes. Both point source and modal initializations of the pressure field are considered.