Giant electrostatic interaction between two neutral conducting spheres in a uniform electric field: A theoretical study via the multiple-image method

Abstract

The giant interaction force between two neutral conducting spheres in an external electrical field was numerically investigated using the multiple image method. The simulation results coincide with the experimental results better than those using simple dipolar approximation and finite element analysis. For a small-inclined angle, the mutual induction leads to accumulation of unlike charges on the local adjacent surfaces of the spheres, thus producing a giant local electrical field compared with the external electrical field. The attractive force between the spheres is drastically increased. The interaction force peaks at [Formula: see text], where the center line of the spheres is parallel to the external electrical field. A weak repulsive force is found for a large-inclined angle because like charges concurrently appear on the local adjacent surfaces of the spheres. The nature of the attractive and repulsive interaction forces is independent of the radius ratio of the spheres. Analysis of influence of relative position of the spheres on the energy conversion showed that the shear stress could be improved by increasing the mutual electric potential energy and decreasing the interior electric potential energy. A maximum shear stress occurs at [Formula: see text], while the minimum mutual potential energy appears at [Formula: see text]. The discovery of interaction mechanism provides a plausible basis for fabricating new materials of giant electrorheological fluids.