Effects of Gurney Flaps on a NACA0012 Airfoil

Experimental measurements of surface pressure distributions and wake profiles were obtained for a NACA0012 airfoil to determine the lift, drag, and pitching-moment coefficients for various configurations. The addition of a Gurney flap increased the maximum lift coefficient from 1.37 to 1.74, however there was a drag increment at low-to-moderate lift coefficient. In addition, the boundary layer profile measurements were taken using a rake of total pressure probes at the 90% chord location on the suction side. The effective Gurney flap height is about 2% of chord length, which provides the highest lift-to-drag ratio among the investigated configurations when compared with the clean NACA0012 airfoil. In this case, the device remains within the boundary layer. This revised version was published online in July 2006 with corrections to the Cover Date.