Numerical Investigation of Efficient Active Flow Control Around the Airfoil NACA 0015 With Plasma DBD Actuators

Abstract

There are considerable studies to optimize the lift coefficient with the plasma Multi Dielectric Barrier Discharge (MDBD) actuators over the airfoil profiles, either in terms of location or in terms of the number of actuators used. All of these studies focused only on the upper side of the airfoils, ignoring the lower one, which can also undergo significant change on one hand, and on the other hand, the majority of studies don’t take control efficiencies into consideration. For this reason, this study performs tests on both sides (upper and lower surfaces) by changing the location and the number of activated actuators on the airfoil profile, where the first step is to ensure the optimal configuration on the upper surface and then test the lower surface by means of two control configurations: “With” (which induces flow velocity) and “Inverse” (which reduces flow velocity), by installing five actuators on the upper surface and five others on the lower surface of the NACA0015 airfoil profile of 150 mm chord length, where the latter are disposed symmetrically to the upper ones placed uniformly at chordal locations x/c = (0.1, 0.3, 0.5, 0.7, 0.9). The actuators are activated by means of 7 kV in “steady state” (100% duty cycle), with a flow Reynolds number Re  35000, representative of low-to-moderate Reynolds aerodynamic applications such as UAVs and wind-tunnel conditions. The ANSYS Fluent program is adapted for this process, in collaboration with a user-defined function (UDF) compiled with the integrated electric potential module to carry out the computation. The results show promising values in lift and efficiency, especially by identifying three relevant flight modes compared to the baseline mode. The first is the Max Lift Mode, which is detected at 15° and reaches an extreme lift coefficient with a notable lift force gain; the second mode reaches its best values at 10°, also with a maximum lift gain force, where it is remarkable that the actuator near the trailing edge with “Inverse” configuration contributes to improving the result; and finally, the High Efficiency Mode is also detected at 10°, with maximum efficiency and lift coefficient, and a net lift force gain.