Applied Underwater Acoustics

3.6. 3-D Sound Propagation Models

In underwater acoustics, it is surprisingly often sufficient to do the modeling in 2-D, neglecting environmental variations in the azimuthal ϕ direction, for a cylindrical r, ϕ, z coordinate system centered at the source. Different environment parameters can of course be set when computations are made for different receiver azimuths from the source, which is called N × 2-D modeling.

Two important cases where 3-D effects may show up are cross-slope propagation over a sloping bottom and propagation around seamounts. In the former case, the azimuthal direction of a ray is changed when it is reflected at the bottom. As illustrated in the left panel of Fig. 3.22, ray trajectories as projected on the horizontal plane ...