Experiments on extreme wave generation using the soliton on finite background

Freak waves are very large water waves whose heights exceed the significant wave height of a measured wave train by a factor of more than 2.2. However, this in itself is not a well established definition of a freak wave. The mechanism of freak wave generation in reality as well as modeling it in a wave basin has become an issue of great importance. Recently one is aware of the generation of freak wave through the Benjamin–Feir type of instability or self–focussing. Consequently the Non–Linear–Schrodinger (NLS) equation forms a good basis for understanding the formation of freak waves. However, the complex generation of a freak wave in nature within a sea condition is still not well understood, when the non-linearity of the carrier wave is not small. In our study we will focus on the Soliton on Finite Background, an exact solution of the NLS equation, as a generating mechanism for extreme waves. Apart from a numerical investigation into the evolution of a soliton on a finite background also extensive detailed model tests have been performed for validation purposes in the hydrodynamic laboratories of the Maritime Research Institute Netherlands (marin). Furthermore, a numerical wave tank [12] is used to model the complete non-linear non-breaking wave evolution in the basin.