Turbulent pair dispersion as a continuous-time random walk

Abstract

The phenomenology of turbulent relative dispersion is revisited. A heuristic scenario is proposed, in which pairs of tracers undergo a succession of independent ballistic separations during time intervals whose lengths fluctuate. This approach suggests that the logarithm of the distance between tracers self-averages and performs a continuous-time random walk. This leads to specific predictions for the probability distribution of separations, that differ from those obtained using scale-dependent eddy-diffusivity models (e.g. in the framework of Richardson's approach). Such predictions are tested against high-resolution simulations and shed new lights on the explosive separation between tracers.

10 pages, 5 figures

Cited by in corpus (3)

• Continuous Time Random Walks for the Evolution of Lagrangian Velocities
• Explosive Particle Dispersion in Plasma Turbulence
• Intermittency in the relative separations of tracers and of heavy particles in turbulent flows