The Huygens-Fresnel principle in ocean acoustics

The peculiarities of the Huygens-Fresnel principle when applied to acoustic fields given as numerical data arrays are considered. The exact solution of the diffraction problem on the basis of the spatial spectral approach and the most common small-angle approximation of this problem are considered. The spectral approach is shown to be preferable for numerical calculation. However, its applicability is restricted (only for numerical calculations) to the case of finite distances. The results are illustrated by simple test problems.