Calculation of the pressure distribution over the surface of two-dimensional and swept wings with symmetrical aerofoil sections

Abstract

A simple method is described for calculating the pressure distribution on the surface of a thick two-dimensional aerofoil section, at any incidence, in incompressible potential flow. The method has been proposed by F. Riegels and H. Wittich, Refs. 1 and 2. It is particuIarly suitable for practical applications, since knowledge of the section ordinates only is required. This paper gives a complete derivation of the theory including a detailed discussion of the approximations made and their effect on the accuracy of the results. The pressure distributions calculated by the present method are identical withthe exact values for aerofoils of elliptic cross-section, and the numerical values for Joukowsky aerofoils agree well with the exact solutions. Calculations for a typicM practical aerofoil show good agreement with the results from S. Goldstein's method, approximation III, Refs. 3 and 4. The method is extended to sheared wings of infinite span and to the centre-section of swept wings, using tile solution for zero lift from Ref. 16 and the solution for the thin wing with lift from Refs. 10 and 17.