SOLUTIONS OF THE CONSTITUTIVE-EQUATIONS FOR THE FLOW OF AN ELECTRORHEOLOGICAL FLUID IN RADIAL CONFIGURATIONS

Analyses are presented of the effect of radial electric field distribution on the performance on an ideal electrorheological fluid in annular film shear and flow rheometers. Influences of the assumed form of yield stress-electric field relationship are shown. For the parabolic case few problems are raised provided the film thickness to radius ratio is small, though some asymmetry is seen in the flow velocity profiles. When the prospect of a barrier or activation voltage threshold is introduced, significant plug flow formation can be encountered. For high field strengths, where the ER effect is most attractive, a relatively uniform shear rate profile is achieved in a Couette viscometer only at higher operating speeds. In both cases the field distribution is taken to be that of a perfect dielectric and the properties of the fluid as a Bingham plastic.