Couette flow of electrorheological fluids between two concentric cylinders with wallslip

Abstract

The Couette flow of electrorheological (ER) fluids between two concentric cylinders withwall slip is considered in the present paper. ER fluids can be closely approximated asBingham plastics. Based on the Navier slip model in the wall boundaries, thecharacteristics of slip flow, in particular the effects of velocity slip on the location of yieldsurface, are obtained by an analytical method. It is shown that the wall slip has a greateffect on the velocity distribution and the location of the yield surface. In the scope of theslip coefficient discussed, the wall slip velocity increases first with increasing slip coefficient;after reaching a maximum, the slip velocity then decreases on further increase of the slipcoefficient. The moments exerted by ER fluids on the walls decrease as the slip coefficientincreases.