A Lifting Surface Theory for Wings Extending Through Multiple Jets in Separated Flow Conditions

摘要

A lifting surface theory for wing-propeller slipstream interactions in separated flow conditions was developed. The case where the flow over wing portions immersed in the propeller slipstreams (jets) is attached while the flow over the wing outside the jets is separated has been treated in detail. The case where flow is separated both inside and outside the jets may be analyzed in a similar manner. The theoretical development combines non-separated flow analyses based on the Rethorst Lifting Surface Solution with cavitation (separated flow) theory developed by Wu and Wang. A lifting surface representation based on a generalization of Weissinger's approximation was developed. In the separated flow regions, the location of the lifting line and the station where downwash boundary conditions must be satisfied are determined from cavitation theory and/or experimental results. Prediction of aerodynamic characteristics in separated flow conditions is of special concern in the development of tilt wing and deflected slipstream V/STOL aircraft where flow separation may occur during the transitional flight from hovering to cruise. (Author)