A Model and Dynamic Simulation of Electro-Rheological Fluids

An electro-rheological phenomenon was numerically simulated by using a model of polarizable particles under an applied electric field and a molecular-dynamics-like method. The calculated results were compared with measured ones for a poly(sodium methacrylate)/silicone oil fluid under DC and AC fields. In the model, the particles are assumed to be polarizable spheres and to interact each other through their dipole moments under an applied electric field. The electric force used for the simulation was estimated from the experimental dielectric dispersion of the particles for each electric field frequency. The shear stress under Stokes flow was calculated from the results of the dynamic simulation. The calculations showed clustering of spheres between the electrodes and also Bingham behavior of electro-rheological fluids. For the AC field, the calculated shear stress decreased with increasing electric field frequency, and this trend was similar to the experimental result.