Leading Edge and Wing Tip Flow Control on Low Aspect Ratio Wings

On the effect of operating condition on separated-flow control by nanosecond pulse discharge actuators

“…At a ¼ 15 , the most efficient nondimensional forcing frequency is F þ ¼ 0.96 (80 Hz). The most efficient nondimensional forcing frequencies in Figure 6 are also near F þ ¼ 1, which is considered to be the most efficient forcing frequency in Vey et al 29 And it is close to the result of Zhao et al 18 Figure 7 shows the C p distribution on the wing for an actuator at position #3 (x/C ¼ 0.05), in which the electrode is near the separated shear layer. It can be concluded that the separated flow still exists after discharge at a ¼ 20 .…”

Separation Control with Nanosecond-Pulse-Driven Dielectric Barrier Discharge Plasma Actuators

“…Some suggest a more appropriate length scale may be the projected length of the airfoil chord (csin(α)). 38 This is motivated by bluff body aerodynamics where for example the cylinder in cross flow is scaled by its diameter. This scaling renders flat plate airfoil frequency sweep data at various α self-similar under the pretext that the wake thickness is approximated by this simple projection.…”

Plasma-Based Dynamic Stall Control and Modeling on an Aspect-Ratio-One Wing

“…This allowed us to adopt two different flow control strategies. The first was excitation of the separated shear layer known experimentally to be effective on two-dimensional airfoils [31][32][33], namely ; and the second was highfrequency excitation determined by high-fidelity computations [37], namely and 50.…”

“…A well-known method for delaying stall on airfoils and high-aspect-ratio wings is the introduction of periodic leading-edge perturbations [28]. Leading-edge perturbations are also effective when strong three-dimensional effects are present, for example on delta [29,30] and low AR rectangular flatplate wings [31][32][33]. Pulse-modulated dielectric barrier discharge (DBD) plasma actuators are particularly attractive because they are light, low-power, and directly convert electrical power to a fluid-based body force [34][35][36].…”

“…However, there is a large range of reduced frequencies at which maximum and post-stall lift enhancements are maximized. For example, pulse-modulated frequencies of (Cµ=0.002%) were reported for flat plate low AR wings [31][32][33]. On the other hand, recent computational studies on finite wings [37] suggest that leading-edge perturbation (Cµ=0.02%) at excited the laminar separation bubble and can thereby delay separation.…”