Modified Extended Hyperbolic Mild-Slope Equations

A form of hyperbolic mild-slope equations extended to account for rapidly varying topography, nonlinear dispersion relation, wind input and energy dissipation during the process of wave propagation, has been derived from the mild-slope equation modified first in this paper. With the inclusion of the input of wind energy, the resultant model can be applied in some areas where the effect of wind could not be neglected. The wave-breaking mechanism which will cause energy dissipation remarkably, as well as the bottom friction, is introduced and discussed during this derivation. Since the modifying factors have taken plenty of aspects into consideration, the extended equations hold enlarged application and increased accuracy.

WKB APPROXIMATION TO THE MODIFIED MILD-SLOPE EQUATION

WKB approximation for water wave scattering by rapidly varying topography is obtained from a modified mild-slope equation of the general form by Porter (2003). The present WKB solution is reduced to the previous study where shallow water conditions are present. WKB models from the transformed mild-slope equation, without the described bottom curvature modification, show better performance than those by the original developed mild-slope equation. The underlying significance of the present equation is discussed in the context of linear wave scattering. The selected figures representing our results further characterize main feature of this study.