Electro-Rheological Effects in a Flow through a Narrow Slit

Abstract

The Electro-Rheological effect in the flow of suspensions of polarizable particles in a narrow slit is studied. Computer simulation is carried out to investigate the velocity profile and the relation between the flow rate and the pressure gradient. It is shown that at a sufficiently weak pressure gradient, the solvent will pass through a solidified network of particles, so that the average velocity of particles is not equal to that of the solvent. This indicates that the conventional modeling of the Electro-Rheological effect based on the Bingham model becomes inappropriate. An analysis is done based on the two fluid model. This analysis is shown to be consistent with the experiment of Bossis e t a l . (Europhys. Lett. 11 (1990) 133) for the flow of a magnetic suspension in a tube.