The effects of ridge excrescences and trailing-edge control gaps on twodimensional aerofoil characteristics

Abstract

Wind tunnel measurements of the effects on twodimensional section characteristics of square ridge excrescences and of some gaps typical of those found round trailing-edge controls have been made at high subsonic Mach number and at Reynolds numbers up to 15.6 x 10power6, based on section chord length. The incremental drag due to a square ridge was found to be generally underestimated by applying an estimated magnification factor to flat-plate measurements. Trailing-edge control gaps affected lift and pitching moment characteristics of the aerofoil as well as drag. A tentative correlation of the measurements of drag due to spanwise gaps is suggested.