Sedimentation in confined geometry
The most familiar form of driven motion in colloidal dispersions is surely sedimentation. Yet it remains remarkably poorly understood, not least due to the non-linear many-body nature of the problem. We were able to show that, depending on the initial conditions, sedimentation in confined systems can in fact be reduced to a readily soluble problem Royall et al, Phys Rev Lett ,98, 188304 (2007) . However, in the case of a non-uniform initial condition, a Rayleigh-Taylor-Like instability leads to chaotic behaviour and network formation. Nonetheless, inclusion of hydrodynamic coupling in computer simulations allows this non-equilibrium emergent behaviour to be quantitatively reproduced.