Mixing in a Meandering Jet: a Markovian Approximation

In this paper we investigate mixing and transport in correspondence of a meandering jet. The large-scale flow field is a kinematically assigned streamfunction. Two basic mixing mechanisms are considered, first separately and then combined together: deterministic chaotic advection, induced by a time dependence of the flow, and turbulent diffusion, described by means of a stochastic model for particle motion. Rather than looking at the details of particle trajectories, fluid exchange is studied in terms of markovian approximations. The twodimensional physical space accessible to fluid particles is subdivided into regions characterized by different Lagrangian behaviours. From the observed transitions between regions it is possible to derive a number of relevant quantities characterizing transport and mixing in the