Dynamics of model-stabilized colloidal suspensions in confined Couette flow

Dynamics of model-stabilized colloidal suspensions in confined Couette flow was investigated by using the self-consistent particle simulation method (SC). In this method, the fluid-particle interaction is considered by combining macroscopic flow simulation and microscopic particle dynamics. In detail, the flow field is solved by the finite element method (FEM) incorporating the extra stress correspond to particles in each finite element, and the particle motion is determined by the Brownian dynamics (BD) with the obtained flow field. Model-stabilized colloidal suspensions were subjected to shear flow in confined planar Couette geometry, and the flow behavior and microstructure were investigated. At low shear rates, the suspension in the confined Couette showed low slope region in the shear stress versus shear rate, which means that confinement-induced dynamics exists. As the flow was applied, flow-induced ordered structure was formed close to the wall, which induced wall slip. As the strain increased, shear banded velocity profile was developed through the gap. This result implies that shear banding of the suspension can be induced by the confinement. The effect of confinement was investigated by varying gap distance and volume fraction. This study also shows that the flow behaviors of colloidal suspensions are affected by the formation of flow-induced microstructures.