Investigation on abnormal wave dynamics in regular and irregular sea states. (15th February 2021) - Zhang, H.D.
Abstract: Peregrine breather solution of the nonlinear Schrödinger (NLS) equation can be treated as one of the excellent backbone models for abnormal wave in the ocean. Fully nonlinear numerical simulations performed with the higher-order spectral method reveal that its maximum amplification factor can be larger than the theoretical prediction in the regular background wave and that such breather dynamics has a high probability to persist even in a chaotic environment. Evidently, in both cases the maximum wave height attainable and the corresponding spatial evolutionary distance required are significantly affected by the initial background waves. In fact, whether the abnormal wave induced by breather dynamics can be generated, is mainly a localized behaviour, strongly dependent on the initial wave group energy as well as the detailed structure of this group. Highlights: Growing processes of maximal crest and trough amplitudes within breather packet are periodically modulated and out of phase. One specific example revealed Peregrine breather dynamics has a high probability to persist in irregular background waves. Abnormal wave induced by breather dynamics in irregular background is a local event dependent on group energy and structure.