Electrohydrodynamic Plumes due to Autonomous and Nonautonomous Charge Injection by a Sharp Blade Electrode in a Dielectric Liquid

This paper addresses the numerical investigation of an electrohydrodynamic (EHD) plume induced by a sharp blade electrode in a dielectric liquid. Different injection laws, namely, autonomous and nonautonomous ones, are considered, and the importance of the blade shape is emphasized, especially for nonautonomous injection laws. Different flow regimes arise according to the value of the Reynolds number based on the ionic mobility and the distance d between the blade and the vertical plate. It is found that the critical Reynolds number for which the transition between steady and unsteady regimes occurs depends on the injection law, on the blade shape, on the M parameter, and on the injection strength C. For much higher Reynolds number, the flow turns to be chaotic and behaves as a jet flow with the development of a Kelvin-Helmoltz instability. The use of different sharp blades indicates that a higher electric field at the tip of the blade plays a significant effect on the development of the EHD plume. The plumes have been characterized by their charge density distribution which shows, in the early stages of the simulation, that its dynamics is significantly dependent on the blade shape as well as on the nonautonomous injection law.