Examination of Signal Dispersion in a 3-D Wedge-Shaped Waveguide using 3DWAPE

In this paper, we solve numerically the problem of a broadband pulse propagation in a three-dimensional waveguide. The numerical method used to solve this 4-D (i.e., three space dimensions plus time) acoustic problem is based on Fourier synthesis of frequency-domain solutions. The calculations in 3-D relative to each discrete frequency are done using the fully three-dimensional Parabolic Equation based code 3DWAPE. Numerical simulations are performed considering a source pulse centered at 25 Hz with a bandwidth of 40 Hz, propagating in a 3-D shallow water penetrable wedge-shaped waveguide. The results, displayed as stacked time series vs. depth, exhibit interesting and typical three-dimensional effects as (mode) shadow zones and multiple (mode) arrivals of the propagating signal.