A.C. Characteristics of the Electroviscous Effect

Abstract

The pressure-drop fluctuations induced by the application of an A.C. electric field perpendicular to the flow direction of various dielectric liquids were observed by means of a pressure gauge. In the low-frequency range, the pressure-drop fluctuates periodically, while a phase difference is observed which depends on the A.C. field frequency. The pressure-drop also fluctuates periodically in the high-frequency range but no phase difference is observed. These different properties are attributed to a difference in the conduction process, i.e., injections in the low-frequency range and electrolytic dissociations in the high-frequency range. In both ranges, pressure-drop fluctuations result from the disturbance of the mean flow caused by electroconvection.