The oscillatory squeeze flow of electrorheological fluid considering the inertia effect

The electrorheological (ER) fluid between two circular electrodes subjected to oscillatory squeeze flow is studied theoretically in this paper. The ER fluid is modeled as a bi-viscous fluid with Bingham-like behavior. The inertia due to the oscillatory flow of the fluid is taken into account. The solution is derived in the complex domain. The magnitude of the total reactive force on the upper electrode and its phase lag with respect to the electrode displacement are calculated numerically. The results show that the phase lag is more sensitive to the inertia effect than the magnitude of the reactive force. It is also shown that, within 10% discrepancy in the magnitude of reactive force, the quasi-static model can be used with actuating frequency lower than 400 Hz for the examples studied.