Evolution of particle-velocity correlations in sedimentation

The velocity field of a dilute monodisperse sedimenting suspension is measured as a function of time with the Eulerian particle image velocimetry technique. The sedimentation process is observed to be dominated by vortices of the size of the container in the initial moments after the cessation of mixing, which diminish with time and seem to reach an ultimate size approximate to 15-20 mean interparticle distances. (C) 2001 American Institute of Physics.