Numerical investigation of leading-edge protuberances on high lift, high camber airfoils at low reynolds number

Lift and drag characteristics of a Selig S1223 airfoil with leading edge sinusoidal protuberances are computed using the commercial CFD solver FLUENT and are compared with those of S1223 without protuberances. The amplitudes of the leading edge protuberances are 10%, 8%, and 4% and the wavelengths are 50% and 25% of the mean chord length. For the airfoil with protuberances, the analysis indicates a large decrease in lift in the pre stall region and smaller decreases in the post stall region. Additionally, the critical stall angle of attack is decreased on airfoils with leading edge protuberances. Numerical visualization of the flow indicates a decrease in separation at peaks of the protuberances and an increase in separation at the troughs. The computed results are compared with the experimental data and shows reasonable agreement.