An experimental investigation of a two-dimensional airfoil with boundary layer control has been conducted. Section lift and pitching moment data have been compared to the thin airfoil theory extended to include the effect of jet entrainment. The experimental tests were conducted on a flapped airfoil section, having boundary layer control by blowing, mounted between parallel walls within a wind tunnel test section. Special experimental techniques, involving the control of the tunnel wall boundary layer by blowing, were employed. The experimental technique of wall boundary layer control and problems associated with two-dimensional testing are discussed. Results from the experimental data have shown, for the range of flap deflections tested, the effectiveness of boundary layer control for increasing the lift of a flapped wing section and the effectiveness of airfoil leading edge blowing as a supplement to an unpowered mechanical flap. Results of the test section performance indicate two-dimensional flow was achieved for the basic airfoil section with quasi-two dimensional flow being established for the flapped airfoil configurations through the use of the tunnel wall boundary control technique. Good correlation between experimental data and the entrainment theory was obtained with respect to lift. Pitching movement correlation showed only fair agreement with the entrainment theory.
