Brownian demixing and wall effects in sedimenting suspensions of orientable particles.

ABSTRACT

We describe the Brownian demixing of sedimenting suspensions, a recently discovered phenomenon in which increases in the thermal energy can destabilize a system of orientable particles subjected to a torque to fluctuations in concentration. Through use of Brownian dynamics simulation and a mean-field analysis, we demonstrate that demixing occurs in a model system composed of slender rigid rods sedimenting between no-slip walls. Additionally, we describe the effects of wall separation distance on suspension stability.