SOME NONLINEAR BEHAVIOUR OF FREAK WAVES AND ENVELOPE SOLITONS

摘要

The nonlinear Schroedinger-like equations are widly used models for investigating the evolution of surface gravity waves with narrow-banded spectra. We numerically compare one of tee simplified models with a fully nonlinear one. In particular, we study the long time evolution of wave groups. Although the simplified model predicts the right number of soliton formed, their behaviour and long time evolution is not well described. SoIitons interact differently with the two models. During the interaction, freak waves are formed. Their occurence is more frequent with the fully nonlinear model. A more interesting phe-nomemon is, during the formation of freak waves, the wave enve-lope oscillates rapidly. This "intermittence" is not at all predicted by any weakly nonlinear model.