Three-vortex quasi-geostrophic dynamics in a two-layer fluid. Part 2. Regular and chaotic advection around the perturbed steady states

Abstract

AbstractWe study fluid-particle motion in the velocity field induced by a quasi-stationary point vortex structure consisting of one upper-layer vortex and two identical vortices in the bottom layer of a rotating two-layer fluid. The regular regimes are investigated, and the possibility of chaotic regimes (chaotic advection) under the effect of quite small non-stationary disturbances of stationary configurations has been shown. Examples of different scenarios are given for the origin and development of chaos. We analyse the role played by the stochastic layer in the processes of mixing and in the capture of fluid particles within a vortex area. We also study the influence of stratification on these effects. It is shown that regular and chaotic advection situations exhibit significant differences in the two layers.