Beyond passive: chaotic transport in stirred fluids

We review selected recent developments on the role of chaotic advection in the dynamics of nonpassive particles. This topic is fundamental to understanding or controlling transport of energy and mass in laminar flows and in turbulent flows possessing long-lived coherent structures, and is finding applications in many areas of mechanical, chemical, and biological engineering. To this end, we provide a general framework for description of particle motion in both discrete and continuum representations. Nonpassive behavior addressed includes particle inertia, self-propulsion, diffusion due to Brownian motion and reactive particles, in particular in relation to chaotic advection. This review makes no attempt at an exhaustive overview of the dynamics of nonpassive particles, but instead concentrates on a number of cases we believe are illustrative for the field. Its primary purpose therefore is to provide an extensive introduction for young researchers and nonexpert scientists that may serve as a starting point for further studies.