A three-dimensional azimuthal wide-angle model for the parabolic wave equation

In predicting wave propagations in either direction, the size:of the angle of propagation plays an important role; thus, the concept of wide-angle is introduced. Most existing acoustic propagation prediction models do have th e capability of treating the wide-angle but the treatment, in practice, is vertical. This is desirable for solving two-dimensional (range and depth) p roblems. In extending the two-dimensional treatment to 3 dimensions, even t hough the wide-angle capability is maintained in most 3D models, it is stil l vertical. Owing to the need of a wide-angle capability in the azimuth dir ection, this paper formulates an azimuthal wide-angle wave equation whose t heoretical development is presented. An illustrative example is included to demonstrate the need for such azimuthal wide-angle capability. Also, a com parison is shown between results using narrow-angle and wide-angle equation s separately.