Micro-meso-macroscale responses of non-colloidal suspensions undergoing dipolar interactions in an electric field: effects of confinement and shear flow*

The dipolar response of non-colloidal dispersions driven by an electric field has led to a class of smart material known as electrorheological fluids. Even though extensive effort has been made to quantify the macroscopic characterizations of such a system, a robust connection of its macroscale properties to the particle-level (micro) and cluster-level (meso) responses is largely unexplored. To this end, we use a large-scale Stokesian dynamics simulation to systematically draw this connection for a range of volume fractions up to a highly concentrated regime. First, we will quantify the volume fraction-dependence of the multiscale responses. Our results reveal different behaviors of structural formation for various concentration regimes with a transition at a specific volume fraction. Second, we will characterize the effect of confinement by applying different levels of confinement. Confinement seems to manipulate the structures primarily at the mesoscopic level, which could link the change in the macroscopic properties. Lastly, we will discuss the degradation of the particulate structures across the length scales due to an external shear flow.