Computation of the velocity field induced by a planar source distribution approximating a symmetrical non-lifting wing in subsonic flow

Abstract

The singular double integrals which arise in the calculation of the components of perturbation velocity due to a swept wing with given thickness distribution by linearised theory, have been evaluated by a numerical method. Two computer programs have been written, one for points on the wing planform and one for points off. Following the techniques adopted by Sells, the integral over the wing is constructed from the sum of analytic spanwise integrals taken along lines of local sweep. The results obtained were tested against calculations by Freestone for points on the wing planform for both sheared and tapered wings. Further comparisons for points on the wing surface were made with results by the method of A. M. O. Smith.