Using Passive Flow Control Methods for an Asymmetric Airfoil in Turbulent Flow

This paper investigates the feasibility of controlling turbulent incompressible flow around an asymmetric Clark Z airfoil by passive blowing of air through perforated surface areas from high-pressure regions to low-pressure regions, as well as by supplying an external pressure flow through the airfoil leading edge and then directing it to the lower side of the airfoil. The studies are performed for chord-based Reynolds numbers Rec = (0.40- 1.28) × 10⁶ and angles of attack ranging from –6° to 6°. It is shown that this control method is ambiguous and highly sensitive to the extent of the mass-transfer region, its chordwise position, the angle of attack, and the Reynolds number. However, in some cases, it provides a 4–5% reduction in the airfoil profile drag and an increase in its lift, which improves the airfoil aerodynamic efficiency.