High-lift enhancement using active flow control

Fluidic-based active flow control is employed to enhance the high-lift performance of an airfoil equipped with a single-element flap. Spanwise periodic flow injection from arrays of fluidic jet actuators downstream of the juncture between the main airfoil body and the flap is used to manipulate vorticity concentrations near the airfoil surface, leading to a significant increase in the extent of flow attachment along the flap. This results in a substantial increase in lift at large flap deflections that is independent of Rec (at δ = 40°, Re_c = 6.7{bullet operator}10⁵ and α = 4°, the lift is increased by as much as ΔC_L = 1.40, or 65% relative to baseline). By integrating the jets into the airfoil using appropriately designed orifice configurations, the momentum coefficient C_μ required for a given lift increment can be reduced significantly.