Modelling of a nanosecond surface discharge actuator

Abstract

Surface dielectric barrier discharges (SDBDs) can modify the boundary layer of a flow and are studied as a possible means to control the flow over an airfoil. In SDBDs driven by sinusoidal voltages in the 1–10 kHz range, momentum is transferred from ions to the neutral gas, as in a corona discharge (ion wind), and the resulting electrohydrodynamic force can generate a flow of several m s−1 in the boundary layer along the surface. In this paper we are interested in a different regime of SDBDs where nanosecond voltage pulses are applied between the electrodes. Recent experiments by the group of Starikovskii have demonstrated that such discharges are able to modify a flow although no significant ion wind can be detected.A two-dimensional self-consistent numerical model of the discharge and gas dynamics in conditions similar to those of these experiments has been developed. The model couples fluid discharge equations with compressible Navier–Stokes equations including momentum and thermal transfer from the plasma to the neutral gas. This is a difficult multi-scale problem and special care has been taken to accurately solve the equations over a large simulation domain and at a relatively low computational cost. The results show that under the conditions of the simulated experiments, fast gas heating takes place in the boundary layer, leading to the generation of a ‘micro’ shock wave, in agreement with the experiments.

Electrohydrodynamic Thrust for In-Atmosphere Propulsion

“…DBD actuators have demonstrated their ability to prevent the boundarylayer detachment on airfoils at moderate Reynolds number (i.e., Re < 10 6 ) but hardly affect the flow at higher Reynolds number. Many experiments [16] and fully coupled numerical computations [17,18] were carried out to solve the fluid dynamic, ion chemistry as well as transport in time-dependant electric fields.…”

Simulation of the discharge propagation in a capillary tube in air at atmospheric pressure

“…Kulikovsky, 1997] is used to simulate the discharge propagation. To take into account the different dielectric permittivities in air and in the dielectric tube, we use Poisson's equation with variable coefficients [Unfer and Boeuf , 2009]:…”

“…In fact, this coefficient is poorly known in air and then in many studies of dielectric barrier discharges in air, photoemission is often neglected [e.g. Unfer and Boeuf , 2009]. In this work, for the results presented in Section 3.2 to 3.4, photoemission is not included.…”

“…In fact, the value of this coefficient is poorly known in air and then in many studies of dielectric barrier discharges in air, photoemission is often neglected [e.g. Unfer and Boeuf , 2009]. In this work, we propose to carry out simulations without photoemission and then to take it into account with different values of the photoemission coefficient to study its influence on the discharge dynamics.…”

Surface charge deposition inside a capillary glass tube by an atmospheric pressure discharge in air

“…In dielectric barrier discharges, surface charges deposited on dielectrics may have a significant influence on the discharge propagation as in surface dielectric barrier discharges studied for flow actuators [5][6][7]. In the work of Soloviev [6] the profile of surface charge density for a positive discharge has been calculated.…”