Experimental Investigation of Airfoil Separation Control Using Dielectric Barrier Discharge Actuator

Dielectric Barrier Discharge plasma actuators have emerged as a highly practical Active Flow Control solution due to their low weight and cost, fast response time, and ease of installation. Active control with pulsed Dielectric Barrier Discharge plasma actuator of laminar separation for a wing section with NLF(1)-0115 airfoil at pre-stall angle-of-attack was investigated for chord-based Reynolds numbers in the range 20,000 to 100,000. For the wind tunnel experiments, a fiberglass wing model equipped with surface microphones and pressure taps was designed and built. Phase-locked Particle Image Velocimetry and unsteady pressure measurements from the surface microphones capture the dynamics of the shear-layer roll-up and the response to periodic forcing. With time-periodic actuation, the vortex shedding is organized and the flow separation is dramatically reduced for the lower Reynolds numbers. As a result, the lift is increased and the pressure drag is decreased. Time histories and frequency spectra of the microphone data reveal the growth of instability waves and the breakdown to turbulence. These findings provide a baseline understanding for future closed-loop Active Flow Control experiments.