A Method to Compute the Pressure Distribution on a Wing Section, Using the Experimental Slope of Lift Curve

Abstract

Potential theory of the pressure distribution on a wing section shall always give the values bigger than the ones obtained from the experiments in a viscous flow. It comes from the viscous effect due to the boundary layer around a wing section. The boundary layer on the suction side of a wing section grows thicker than the one on the pressure side, when the wing section has some angle of attack against a viscous flow. Such unequality in the boundary layer thickness hydrodynamically brings the virtual reduction of the attack angle as well as the camber ratio of a wing section due to the decline of the nose-tail line, or effectively distorts the section shape so that the trailing edge should be slightly raised up from the original. The author proposes a practical method to form the distorted wing section, in which the experimental slope of lift curve is utilized, and by which the pressure distribution can be computed for a wing section in a real flow. The pressure distribution thus computed for an exemplified wing section is in rather good agreement with the experimental result.