Dispersion of passive tracers in a confined convective flow

A confined convective flow is experimentally studied at different Rayleigh numbers. Particle Tracking Velocimetry (PTV) technique is used both to reconstruct Lagrangian trajectories and to evaluate Eulerian flow field. Dispersion properties of the flow are investigated by means of Lagrangian statistics on particle displacements, For each run of the experiment, single particle statistics have been evaluated both on the whole set of trajectories and by selecting trajectories starting in phase from different region of the flow domain. These regions are identified according to the local geometrical characteristics of the velocity field. (C) 2001 Editions scientifiques et medicales Elsevier SAS