Dielectric barrier discharge (DBD) plasma actuators are an attractive option for separation control, lift enhancement, and drag reduction. Some plasma actuators feature optimized electrode shapes, electrical waveforms to maximize the aerodynamic forces at higher angles of attack. Here, we analyze the performance of a direct current augmented DBD (DBD - DCA) actuator with a sawtooth shape exposed electrode. The active electrode was positioned at 18% chord and the electrode at 48% chord of NACA 0012 airfoil. Wind tunnel experiments were conducted at wind speeds of 15 - 25 m/s, corresponding to Reynolds number Re = 201k - 335k. Lift coefficient (C$_L$), drag coefficient (C$_D$), and pitching moment coefficients (C$_M$), were measured with and without plasma actuation for angles of attack $alpha$ = 0$^o$ - 8$^o$ and the DCA electrode potential ($varphi_{DC}$) was varied from 0 kV to -15 kV. With energized DCA electrode, the C$_L$ increases up to 0.03 and the C$_D$ decreases by 50% at 15 m/s flow speeds and 0$^o$ angle of attack, the results are similar throughout the range of $alpha$. The effect of the actuator at higher Re diminishes, suggesting that the maximum control authority could be achieved at lower wind speeds.
تحميل البحث