Contents lists available at ScienceDirect Journal of Electrostatics journal homepage: www.elsevier.com/locate/elstat Velocity profiles of an electrohydrodynamic flow generator: CFD and experiment Rafał Gałek a,∗ , Piotr Strzelczyk b a Department of Thermodynamics, Faculty of Mechanical Engineering and Aeronautics, Rzeszów University of Technology, 8 Powstańców Warszawy Ave., 35-959, Rzeszów, Poland b Department of Fluid Mechanics and Aerodynamics, Faculty of Mechanical Engineering and Aeronautics, Rzeszów University of Technology, 8 Powstańców Warszawy Ave., 35-959, Rzeszów, Poland ARTICLE INFO Keywords: Electrohydrodynamics Corona discharge Constant temperature anemometry CFD Velocity profile Turbulence intensity ABSTRACT The velocity profiles of the electrohydrodynamic flow generator were investigated experimentally and nu- merically. The generator of a needle-to-cylinder electrode configuration with varying interelectrode distance and supply voltage was studied. Experimental results were obtained with constant temperature anemometry tech- nique and the numerical simulations were performed with Multiphysics Object-Oriented Simulation Environment (MOOSE) framework. The current-voltage characteristic of the device and the relationship between flow velocity and electric current were found out to qualitatively match the results from previous studies. Velocity profiles obtained experimentally and numerically showed varying degree of agreement throughout studied configurations of interelectrode distance and supply voltage. Generally, better agreement was found in cases with lower interelectrode distance, lower turbulence strength and better accuracy of the solution of the electric part of the problem. Some similarities between studied flow and the flow specific for confined jet ar- rangement were observed, although recorded turbulence intensity values were much higher. Turbulence in- tensity profile for the lowest interelectrode distance indicated the existence of the shear layer between jet core and the boundary layer. For other values of the interelectrode distance the shear layer and boundary layer could no longer be distinguished. Nondimensional velocity profiles for all investigated configurations showed high degree of similarity in the jet core region, however the similarity was lost in the remaining part of the flow. 1. Introduction The flow of the fluid in an electrohydrodynamic (EHD) device is essentially an effect of a direct conversion of electric energy into kinetic energy of the medium. It is possible when the electric potential differ- ence in the range of kilovolts is applied to electrodes with significantly different surface curvature radii. For the corona discharge to occur, one of the electrodes should be shaped as a sharp blade, tip or simply a wire with very small diameter. A thin ionization layer is formed in the im- mediate vicinity of the corona electrode as soon as electric potential difference between electrodes reaches certain value, commonly refer- enced as corona onset voltage. Ions produced in that region are in- stantly accelerated in the existing strong electric field towards collector electrode and collide on their paths with neutral molecules of air. The momentum gained by the fluid from these collisions results in the flow of the medium which may be observed macroscopically and practically utilized. In a broader context, flows induced by corona discharge fit into increasingly popular trend towards non-standard or alternative methods of flow generation exemplified by such techniques as synthetic jet [1–3] or piezoelectric actuators [4,5]. Each of these technologies attracts researchers’ attention for quite different reasons, but even among them, electrohydrodynamic flows stand out by the virtue of some unique advantages. Most of them stem from the fact that the flow in EHD devices is generated without employment of any moving parts. Such simplicity completely eliminates the problems with frictional wear, vibrations and noise. Electrohydrodynamic devices have also very low power consumption which makes them particularly suitable as a components of portable equipment. These beneficial features encouraged researchers to propose an application of electrohydrodynamic flow generators as an alternative for more conventional devices such as axial fans. The most prevalent idea is to employ them for heat transfer enhancement in electronic equipment. In Ref. [6]a flow induced by the array of corona electrodes https://doi.org/10.1016/j.elstat.2019.04.003 Received 8 January 2019; Received in revised form 3 April 2019; Accepted 25 April 2019 ∗ Corresponding author. E-mail address: rafalgalek@prz.edu.pl (R. Gałek). Journal of Electrostatics 99 (2019) 19–30 0304-3886/ © 2019 Elsevier B.V. All rights reserved. T