A theory of induced interaction between rotating particles in electrorheological fluids

Abstract

Recent experiments on electrorheological effects provide evidence that the rotation of particles weakens the induced electric forces between dielectric particles. To study the induced electric force exerted on rotating particles phenomenologically, we establish a differential equation to describe the relaxation process of the surface polarized charge distribution on rotating particles in an electrorheological fluid. In the case of a uniformly rotating particle, a general solution to the relaxation equation for the polarized charge is obtained. The surface charge distribution of a two-particle system consisting of a particle at rest and a uniformly rotating particle is calculated. Based on the Green’s function approach, we evaluate the electric potential in both the host and the rotating particle. A formula relating the angular velocity of rotating particle to the induced electric force on the particle is then derived.