Electric wind produced by surface plasma actuators: a new dielectric barrier discharge based on a three-electrode geometry

Abstract

Active flow control is a rapidly developing topic because the associated industrial applications are of immense importance, particularly for aeronautics. Among all the flow control methods, such as the use of mechanical flaps or wall jets, plasma-based devices are very promising devices. The main advantages of such systems are their robustness, their simplicity, their low-power consumption and that they allow a real-time control at high frequency. This paper deals with an experimental study about the electric wind produced by a surface discharge based on a three-electrode geometry. This new device is composed of a typical two-electrode surface barrier discharge excited by an AC high voltage, plus a third electrode at which a DC high voltage is applied in order to extend the discharge region and to accelerate the ion drift velocity. In the first part the electrical current of these different surface discharges is presented and discussed. This shows that the current behaviour depends on the DC component polarity. The second part is dedicated to analysing the electric wind characteristics through Schlieren visualizations and to measuring its time-averaged velocity with a Pitot tube sensor. The results show that an excitation of the electrodes with an AC voltage plus a positive DC component can significantly modify the topology of the electric wind produced by a single DBD. In practice, this DC component allows us to increase the value of the maximum induced velocity (up to +150% at a few centimetres downstream of the discharge) and the plasma extension, to enhance the depression occurring above the discharge region and to increase the discharge-induced mass flow rate (up to +100%), without increasing the electrical power consumption.

Electrical and mechanical characteristics of surface AC dielectric barrier discharge plasma actuators applied to airflow control

“…Another manner to characterize the response time is to observe the whole flow when the discharge is switched on. For instance, Moreau et al (2008a) conducted Schlieren visualizations because they do not require to seed the flow with particles. In fact, this technique enables the visualization of flows in which density gradients are present, because the gray level of the image is proportional to the gas density.…”

“…(Louste et al 2005;Moreau et al 2008b;Sosa et al 2009b), sliding discharges were produced by using the design presented in Fig. 55.…”

Experimental study on dielectric barrier discharge actuators operating in pulse mode

“…[8][9][10] Several parametric and optimization studies have been performed for maximizing the produced body force and induced velocity. [11][12][13][14][15][16] More recently the use of advanced techniques such as nanopulse discharges 17,18 and three-electrode designs 19 have been proposed. The general consensus of these studies is that although the actuators have the potential for efficient flow control at low velocity regimes, their effectiveness decreases with increased Reynolds number.…”

Flow Actuation by DC Surface Discharge Plasma Actuator in Different Discharge Modes

“…In addition, the actuation capacity is limited by an increased gas heating effect at higher discharge currents. Several efforts have been made to overcome these disadvantages by adding a DC shift to the AC power input [28] or by using a meshed electrode [29].…”