Yielded Surface Research Articles

Instability of Taylor–Couette Flow of Electrorheological Fluid

A linearized instability analysis of Taylor–Couette flow between tworotating concentric cylinders of an electrorheological (ER) fluid iscarried out. The ER fluid exhibits a yield stress in addition to theplastic viscosity when an extra electric-field is applied. It can befound that the yield stress plays a dual role in the flow instability.The possibility of the yield surface falling between the cylinders isanalysed. Although small waves appeared on the yielded surface isconsidered, the yielded surface, which has been treated as a freesurface, has little effect on the flow instability. The effects ofaxisymmetric perturbation on the flow instability are presented due tothe axisymmetric of the basic flow. The parameter β in theyield stress formula of the ER fluid is shown to have distinct effectson the flow instability characteristics.