A wake source model for airfoils with separated flow

Abstract

In an extension of an earlier potential-flow theory using conformal mapping and source singularities in the wake region to simulate two-dimensional bluff-body flow, new mapping sequences and additional boundary conditions are presented for the application of the method to lifting airfoils fitted with upper-surface spoilers or lower-surface split flaps of arbitrary size, location, and erection angle. The only empirical input is the base pressure coefficient. Calculations are presented of pressure distribution and lift for several cases of a Joukowsky airfoil fitted with a spoiler or a split flap, and these results are compared with experimental data from wind tunnel tests. Good agreement is found.