Effect of rotation on the electrohydrodynamic instability of a fluid layer with an electrical conductivity gradient
Journal
Physics of Fluids
Journal Volume
22
Journal Issue
2
Pages
1-11
Date Issued
2010
Author(s)
Abstract
The electrohydrodynamic instability of a horizontal rotating fluid layer with a vertical electrical conductivity gradient is considered. An external electric field is applied across the fluid layer to induce an unstably stratified electrical body force. A linear stability analysis has been performed to study the effect of rotation on the onset of electrohydrodynamic instability in the fluid layer. Results show that the instability behaviors depend heavily on the boundary condition of bottom surface. In the case of stress-free condition, rotation enhances the stability and the onset of instability will be dominated by the oscillatory mode once the speed of rotation (or Taylor number) exceeds a critical value. In contrast, in the case of rigid bottom surface, rotation also tends to stabilize the fluid layer and the stationary mode will prevail eventually with increasing Taylor number. However rotation becomes destabilizing as the critical mode shifts from oscillatory to stationary. Moreover, under the same electrical conductivity gradient, the case with stress-free bottom surface is always more unstable than that with rigid bottom surface in the small Taylor number domain. However this situation is reversed at high Taylor number region since the stability of the stress-free case will be enhanced more rapidly than the rigid case.
Type
journal article