2002 Volume 43 Issue 7 Pages 1658-1662
We study the relation between microstructures of electrorheological (ER) fluids and their viscosity change by performing Brownian dynamics simulations of a model ER system both in a static state and in a simple steady shear. From large-scale three-dimensional simulations, it is found that (1) under no shear flow there are two principal phases in microstructural changes: first aggregation of particles into chains oriented along the field direction, and the subsequent slow coalescence of chains into columns, and (2) under a simple steady shear there are three stages in viscosity changes with increasing the field: Newtonian at a weak field, non-Newtonian at a moderate field, and Bingham plastic with yield stress at a high field.
