Special Session 21: Fluid dynamics and PDE

A Hamiltonian Dysthe equation for hydroelastic waves in a compressed ice sheet.
Adilbek Kairzhan
Nazarbayev University
Kazakhstan
Co-Author(s):    Philippe Guyenne, Catherine Sulem
Abstract:
In this talk we consider nonlinear hydroelastic waves along a compressed ice sheet lying on top of a two-dimensional fluid of infinite depth. Based on a Hamiltonian formulation of this problem and by applying techniques from Hamiltonian perturbation theory, a Hamiltonian Dysthe equation is derived for the slowly varying envelope of modulated wavetrains. The derivation is complicated by the presence of cubic resonances. A Birkhoff normal form transformation is introduced to eliminate non-resonant triads while accommodating resonant ones. We also test the newly obtained Dysthe model against direct numerical simulations of the full Euler equations, and very good agreement is observed.