IHS ESDU Second-order method for estimating the subcritical pressure distribution on a two-dimensional aerofoil in compressible inviscid flow. 72025

ESDU 72025 presents a method, accurate to second-order in thickness, camber and incidence. Examples are given of comparisons with a nominally-exact method and it is shown how the method differs from a first-order method widely used as the basis for the calculation of pressure distributions on finite swept wings and on aerofoils in compressible viscous flow. A critical evaluation of the second-order method is referenced, wherein it is shown that over a wide range of aerofoil shapes, incidence and Mach number, pressure distributions calculated by the second-order method differ appreciably from nominally-exact calculations only for local regions of aerofoils where high local surface curvature occurs and over the first 20 per cent, or so, of chord for aerofoils having the bluffer leading-edge profiles. Two suggested techniques for enumerating the method are outlined and reference is made to a computer program which has been used to obtain results from the method.