Measurement of the charge on dieletric surface of a DBD plasma actuator

Summary form only given. Over the past two decades, non-thermal plasmas have been intensively investigated for active airflow control. The main goal of the majority of these studies is to improve the aerodynamic characteristics of the studied geometries by drag reduction and/or lift enhancement. Compared with the conventional airflow control method using mechanical parts and hydraulic systems, one of the great advantages of plasma actuators, called electrohydrodynamic (EHD) actuators, is the absence of moving parts, which leads to faster action. Since many years, plasma actuators have used mainly the surface dielectric barrier discharge (SDBD) whose arrangement consists of two thin electrodes placed asymmetrically on each side of a thin dielectric layer. In order to understand the mechanism of the interaction between the plasma and the extern airflow, studies of the discharge characteristics have been realized as well as measurements of the electrohydrodynamic force and the ionic wind or modifications of the discharge behavior to increase the mechanical performances as described by Benard and Moreau in their review paper. Usually, the SDBDs, driven by AC high voltage power supply with different frequencies and amplitudes, produce a succession of micro-discharges and each micro-discharge modifies the electric charge remaining in dielectric surface. It is important to understand how the discharge characteristics affect the SDBD operation. Consequently, it is essential to investigate the surface charging phenomenon under a variety of conditions. In this work, the method developed in our team for time dependent measurement of the surface charge has been firstly compared with the measurements using an electrostatic voltmeter. A good agreement between these two methods was found. Then, this simple method was used to quantify the charge deposited by a unique negative or positive pulse and for different pulse durations and amplitudes. Our results show i) that the quantity - f deposited charge varies linearly with voltage and ii) that for a pulse duration less than 5 ms, the quantity of charge is independent of the pulse duration. Moreover, charges obtained for different dielectric materials and SDBD arrangements have been measured.