Experimental Study of Flow Around Stepped NACA 0015 Airfoils at Low Reynolds Numbers

This study investigates the flow around Kline-Fogleman (KF) airfoils using Particle Image Velocimetry (PIV) in a wind tunnel at Reynolds number Re = 6.8 × 104. Three configurations are tested: a clean NACA 0015 airfoil and two modified versions with a step on either the pressure or suction side. Velocity fields are used to calculate lift via the Kutta-Joukowski theorem. Results show that the KF airfoil with a step on the pressure side achieves a 14.8% higher maximum lift coefficient and delayed stall. In contrast, placing the step on the suction side reduces maximum lift by 4%. The KF airfoil with pressure-side step shows potential for low Reynolds number applications where higher lift and larger stall angles are required.