Analisi Birkhoff Normal Form and long time existence for periodic gravity water waves Roberto Feola 03-07-2018 - 16:00 Largo San Leonardo Murialdo,1 - Pal.C - AULA 211
We consider the gravity water waves system with a periodic one-dimensional interface in infinite depth and give a rigorous proof the conjecture of Zakharov and Dyachenko. More precisely, we provide a reduction of the equations to Birkhoff normal form and prove the integrability of the water waves Hamiltonian up to order four. As a consequence, we also obtain a long-time stability result for periodic solutions: perturbations of a flat interface that are of size $e$ in a standard Sobolev space lead to solutions that remain regular and small up to times of the order $e^{-3}$. |