EXPERIMENTAL RESULTS ON AEROFOIL MANIPULATORS AT HIGH SUBSONIC SPEEDS

An extensive series of measurements of the boundary layer development and drag downstream of aerofoil manipulators have been made in the hig h speed tunnels at Cambridge. This work forms part of a combined study with the University of Poitiers into the possible drag reducing prope rties of manipulators and was supported by Airbus Industrie. Overall t he test results showed that the reduction in turbulent skin-friction d ownstream 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 po ssible although in certain cases the overall drag penalty was small. T his 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 actua l drag reduction obtained was found to be extremely sensitive to chang es in the aerofoil shape and incidence.