Effect of dynamical traps on chaotic transport in a meandering jet flow

TL;DR

This paper investigates how dynamical traps influence chaotic transport in a meandering jet flow, revealing how different trap types affect particle flight statistics and mixing behavior.

Contribution

It introduces a phenomenological explanation linking dynamical, topological, and statistical properties of chaotic mixing through the concept of dynamical traps in phase space.

Findings

Short flight PDFs are affected by rotational-islands and saddle traps.

Long flight statistics are influenced by ballistic-islands traps.

Dynamical traps explain peculiar transport phenomena in the flow.

Abstract

We continue our study of chaotic mixing and transport of passive particles in a simple model of a meandering jet flow [Prants, et al, Chaos {\bf 16}, 033117 (2006)]. In the present paper we study and explain phenomenologically a connection between dynamical, topological, and statistical properties of chaotic mixing and transport in the model flow in terms of dynamical traps, singular zones in the phase space where particles may spend arbitrary long but finite time [Zaslavsky, Phys. D {\bf 168--169}, 292 (2002)]. The transport of passive particles is described in terms of lengths and durations of zonal flights which are events between two successive changes of sign of zonal velocity. Some peculiarities of the respective probability density functions for short flights are proven to be caused by the so-called rotational-islands traps connected with the boundaries of resonant islands (including the vortex cores) filled with the particles moving in the same frame and the saddle traps connected with periodic saddle trajectories. Whereas, the statistics of long flights can be explained by the influence of the so-called ballistic-islands traps filled with the particles moving from a frame to frame.