Experimental study of a plane turbulent wall jet induced by a dielectric barrier injection in dielectric liquid

A wall jet is a flow which is particularly interesting from both practical and theoretical points of view. Most of the times it is used to inject turbulence and shear stress into a flow directed along a wall. In the most frequent engineering applications (cooling or heating surfaces, atomization of fluids, etc ...) the turbulence structure in the vicinity of the surface of the wall is a "key issue" for its performance. In this study an experimental setup based on the dielectric barrier injection (DBI) phenomenon is proposed to generate a wall jet in a dielectric liquid. The charge injection is obtained by using two metallic electrodes separated by a dielectric flat plate. One of them is a blade placed on the upper surface of the plate and the other one a metallic strip immersed in the dielectric solid. An AC square voltage is applied between the two electrodes. The injection of electric charges close to the surface of the plate makes the fluid flow and generates a turbulent wall jet. The velocity of the flow has been measured by Particle Image Velocimetry. A comparison with classical wall jets has been done in order to point out the specific characteristics of the electrical wall jets. PIV measurements have been also performed and show that the velocity depends mainly on the applied potential and can reach 0.14 m/s.