TRANSFORMATION OF WAVE GROUPS IN A DIRECTIONAL SEA

The purpose of this study is to determine wave group evolution by investigating the transformation of multi-directional spectra at constant depth and on a sloping beach. The transformation of wave groups can be evaluated by computing multi-directional nonlinear waves based on the third-order Zakharov equation. Initial conditions for numerical simulation were characterized by the Gaussian spectrum for several values of significant wave heights and water depths. The numerical results show that the distribution of the energy processes affects the evolution of the wave groups, and the characteristics of directional wave groups can be reproduced through the Zakharov equation model. Finally, field observation data at Akabane beach were used to demonstrate the transformation of wave groups in a real directional sea.