Response time of an ER-fluid under shear and flow modes

The response times of an ER-fluid in shear and flow modes under the effect of AC- and DC-fields were investigated experimentally. In shear mode, the response time was obtained under the effect of different shear rates and electrical field strengths by comparing the shear stress measured statically with that measured dynamically. The response times in shear mode decreased with increasing the field strength and decreasing the shear rate. In flow mode, the response times of the ER-fluid under various electric field strengths and flow rates were determined from the pressure measurements in channel flow. The response times in flow modewere exponentially decreasedwith the increase of the volumetric flow rate and the electric field strength. In both modes, increasing the frequency of the AC-field led to increase of the response time of the ER-fluid.