HRT

Abstract

Statistical mechanics of vortex patches can provide models for potential vorticity mixing with the constraints of fluid incompressibility and energy conservation. This leads to the self-organisation of turbulence into large coherent structures. We can apply a similar approach to the vertical mixing of fluid elements with different densities. This leads to a model of vertical mixing which involves the competition of an eddy diffusivity with sedimentation of fluid elements. In addition to these two processes, the straining of fluid elements by eddies must be included. The behaviour of the resulting model will be discussed for different cases of vertical mixing in a stratified fluid.