Abstract
Theoretical investigation was made on the hydrodynamic characteristics taking into account the effect of the particles of electrorheological fluid (ER fluid) which is a type of colloidal dispersion. First of all, the numerical calculation supposing the uniform dispersion of each sphere particles were made and the results were compared with the experimental data at the case of rotating flow in concentric cylinder as one of the cases of fluid flow. Secondly, the quantitative or qualitative difference between them was investigated under the assumption that the cause of the difference is aggregation of the particles, and the difference was estimated with using the equation of the increment of viscosity by applying an electric field taking into account the aggregation.
