Focusing models for generating freak waves

A 2-D extreme wave focusing model is presented onthe basis of enhanced high-order spectral (HOS) numerical method,validated with the experimental and theoretical results, and applied toinvestgate the effect of wave-wave nonlinear interaction on the wavefocusing amplitude. Based on improved Longuet-Higgins wave model, four wavefocusing models for freak wave generation are proposed: 1.extreme wave modelwith random wave model; 2. extreme wave model with regular wave model; 3.wave focusing model from phase-interval modulation; 4. wave focusing modelfrom wave number modulation with the same phase. With the application ofdifferent energy distribution techniques in the four wave focusing models,freak wave with differentvalues of H_\max/H_s are obtained in thefinite space and time domains.