Experimental results on aerofoil manipulators at high subsonic speeds

Abstract

An extensive series of measurements of the boundary layer development and drag downstream of aerofoil manipulators have been made in the high speed tunnels at Cambridge. This work forms part of a combined study with the University of Poitiers into the possible drag reducing properties of manipulators and was supported by Airbus Industrie. Overall the test results showed that the reduction in turbulent skin-friction downstream of the device did not compensate for the drag of the device itself in any of the cases studied, thus no overall drag saving was possible although in certain cases the overall drag penalty was small. This finding suggests that such devices may have a use in regions where a local reduction in skin-friction (and hence possible heat transfer) is needed and a low level of loss can be accepted. However, the actual drag reduction obtained was found to be extremely sensitive to changes in the aerofoil shape and incidence.