Interfacial instability: a new approach to transient EHD motion with unipolar injection

The electrohydrodynamic (EHD) instability of an insulating liquid subjected to a transient unipolar injection is investigated. A novel model based on the EHD instability of the interface between the space-charge layer in front of an injecting electrode and the bulk of an insulating liquid is proposed. One of the important features for transient unipolar injection, the time delay, is studied using this model. There is good agreement between times predicted by this model and published data. It appears that the EHD instability is governed by the dynamics of the interface rather than by the development of a quasi-static critical voltage across the space-charge layer