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Abstract

A new analytical method, based on Theodorsen and Hariharan and Leishman’s work, which includes the influence of overhang on unsteady drag, is established to study the two-dimensional aerodynamics of trailing edge flap (TEF) airfoils with overhang. The drag of several TEF airfoils with overhang is calculated and precision improved effectively by the present methods in both steady and unsteady cases. The influence of flap chord ratio (the ratio of the flap chord to the airfoil chord) and overhang ratio (the ratio of overhang value to the flap chord) on steady and unsteady drags is analysed, which showed that (1) appearance of overhang increases the drag significantly, and (2) increase in overhang ratio results in augmenting amplitude and phase lag of drag coefficient. Unsteady lift force, pitching moment and hinge moment, of the TEF airfoils with overhang, for the sake of completeness, are also discussed together with the drag.

Keywords

trailing edge flap overhang drag

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The unsteady drag of airfoils having trailing edge flaps with overhang in subsonic flow

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