Large-scale streamers in the sedimentation of a dilute fiber suspension.

We experimentally characterize structures formed during the sedimentation of rigid fibers of high aspect ratio at small Reynolds number using particle image velocimetry. Measurements show the existence of large-scale streamers during early stages of the sedimentation process, consistent with previously published theory and numerical simulations. At longer times, the cell-wide inhomogeneities evolve into smaller-scale streamers. Measurements of spatially averaged fiber velocities and velocity fluctuations are also presented.