  We study how varying the P \'eclet number (Pe) affects the steady state
sedimentation of colloidal particles that interact through short-ranged
attractions. By employing a hybrid molecular dynamics simulation method we
demonstrate that the average sedimentation velocity changes from a non-
monotonic dependence on packing fraction {\phi} at low Pe numbers, to a
monotonic decrease with {\phi} at higher Pe numbers. At low Pe number the pair
correlation functions are close to their equilibrium values, but as the Pe
number increases, important deviations from equilibrium forms are observed.
Although the attractive forces we employ are not strong enough to form
permanent clusters, they do induce transient clusters whose behaviour is also
affected by Pe number. In particular, clusters are more likely to fragment and
less likely to aggregate at larger Pe numbers, and the probability of finding
larger clusters decreases with increasing Pe number. Interestingly, the
life-time of the clusters is more or less independent of Pe number in the range
we study. Instead, the change in cluster distribution occurs because larger
clusters are less likely to form with increasing Pe number. These results
illustrate some of the subtleties that occur in the crossover from equilibrium
like to purely non-equilibrium behaviour as the balance between convective and
thermal forces changes.
