Large scale energy transfer from an internal gravity wave reflecting on a simple slope

Abstract

Several processes lead to mixing and transport in the ocean, among those being the interaction of the internal gravity wave field with bottom topography. The latter process is considered in the present work, through joint laboratory experiments and numerical simulations. The basic configuration is a plane wave of finite extent reflecting onto a sloping bottom in a uniformly stratified fluid. As expected, the interaction between the incident and reflected waves produces harmonic waves, but an irreversible wave-induced mean flow grows in the interacting region between those waves, whose amplitude may be larger than that of the incident wave. This mean flow appears to be controlled by nonlinear and dissipative effects associated with the reflected wave component. Unlike in the atmosphere, the role of this wave-induced mean flow has been completely overlooked in the ocean. © 2013 The Authors.