Interaction Between Long Internal Waves and Free Surface Waves in Deep Water

Abstract

We consider a density-stratified fluid composed of two immiscible layers separated by a sharp interface. We study the regime of long internal waves interacting with modulated surface wave packets and describe their resonant interaction by a system of equations where the internal wave solves a high-order Benjamin-Ono (BO) equation coupled to a linear Schrodinger equation for the envelope of the free surface. The perturbation methods are based on the Hamiltonian formulation for the original system of irrotational Euler’s equations as described in Benjamin-Bridges and Craig Guyenne-Kalisch. We also establish a local well posedness result for a reduced BO-Schrodinger system using an approach developed by Linares-Ponce-Pilod.