On the Design of Thin Subsonic Airfoils

The inverse problem, which determines an airfoil geometry given some specified surface pressure, is considered in the subsonic, thin-airfoil limit. The full governing equations are expanded in powers of the thickness ratio and solved to second-order. The two sequential formulations contain free parameters, which are fixed by invoking “Kutta-type” conditions related to trailing edge closure. The correctness of the basic approach is demonstrated by using known classical examples for the simpler first-order problem.