Brownian Dynamics Simulation for Bimodal Suspensions of Oblong-Particles under Shear Flow

Abstract

Brownian dynamics simulations of the shear flow for bimodal suspensions of oblong-particles were carried out. Two kinds of oblong particles were used: two-sites and four-sites model particles with the interparticle potential of a repulsive Lennard-Jones potential. At low shear rates, the flow-induced orientation of the system greatly depends on a mixture ratio of two-sites and four-sites particles. There is a transition to a hexagonal arrangement of string structure in the gradient-vorticity (y-z) plane at high shear rates, and the shear rate where the structural transition occurs becomes lower with increasing the number of four-sites particles. The formation of the string structure requires a large shear strain after an imposition of shear. Concerning the rheological properties of the systems, the number of four-sites particles affects the sear-thinning viscosity and normal stress effect. Furthermore, the formation of the string structure causes significant changes in the viscosity and the first normal stress difference.