Aerodynamic Investigations of a Morphing Membrane Wing

This paper presents the aerodynamic analysis of a morphing wing configuration using a compliant membrane as lifting surface to enable large variations of the planform geometry (aspect ratio and sweep angle) and airfoil shape. Comprehensive tests of a specifically designed wind-tunnel model including force measurements, deformation measurements, surface flow visualizations, and wake flow measurements are used to assess the aerodynamic behavior and the performances of this morphing wing. The results of the force measurements performed on five different wing configurations ranging from a high-aspect-ratio, straight wing to a highly swept back, low-aspectratio configuration show that the active variation of the wing planform effectively alters the lift and drag characteristics in such a way that relatively high lift-to-drag ratios can be maintained over a broad range of flight conditions.Inaddition,duetoitsmaterialproperties,thewingsurfacepassivelydeflectsunderaerodynamicloading, whichaffectstheairfoilshapeaccordingly.Itresultsin anadditional dependencyoftheaerodynamiccharacteristics on the flow conditions, which can be used for passive flow control.

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