Design and test of a series of annular aerofoils

Abstract

The results of a series of wind tunnel tests involving velocity, surface pressure and force measurements on six annular aerofoils are presented together with details of the design procedure which was based on that given by Kuchemann and Weber. It is shown that theoretical predictions agreed well with experimental results when the foils were in the design condition, i.e. uniform inflow at zero incidence. Pressure, lift and drag measurements were also made on the foils at incidence, and the results differed somewhat from predictions of lifting surface theory. Three foils were further tested with concentric centre-bodies and three others in an axisymmetric inflow; in both cases the theoretical predictions agreed well with experimental results.