Diffusion properties of test particles in a two-dimensional fluid

Abstract

The authors study by means of numerical simulation, the diffusive behaviour of test particles in a two-dimensional fluid, whose velocity field passes from periodic to chaotic motion. They show that there exists no relation between the diffusion coefficients and the degree of chaoticity of the Lagrangian motion. This is related to the intermittent character of the diffusive process; this behaviour, on a qualitative ground, may be interpreted in terms of intermittent maps.