  We investigate the dynamics of granular columns of point particles that
interact via long-range hydrodynamic interactions and fall under the action of
gravity. We investigate the influence of inertia using the Green's function for
the Oseen equation. The initial conditions (density and aspect ratio) are
systematically varied. Our results suggest that universal self-similar laws may
be sufficient to characterize the temporal and structural evolution of the
granular columns. A characteristic time above which an instability is triggered
(which may enable the formation of clusters) is also retrieved and discussed.
