Diffractive analysis of backscatter from wave-crest-like objects

The backscattering from surface profiles approximating the crests of steep water waves has been modeled using diffraction theory. The diffractive backscattering from rounded-apex wedges is due to diffraction from curvature discontinuities, and can be predicted with apex radii as small as one-third of a wavelength using standard diffraction coefficients provided that heuristic corrections are applied to account for the small radii and finite surface conductivity. The same diffraction theory can also be used to model the backscattering from surfaces that approximate the early formation of a jet on a breaking crest, although accuracy is a bit poorer when the crest-feature radii are one-third wavelength. This confirms that the limitations found in a previous study are due to the limitations of the model itself, and not due to the averaging of surface curvatures that were needed to allow the application of the model.