Experimental Aerodynamic Comparison of Active Camber Morphing and Trailing-Edge Flaps

Abstract

Unlike hinged flaps (for example, ailerons, elevators, and rudders), camber morphing devices vary camber distribution in a smooth and continuous way, resulting in aerodynamic efficiency improvements due to the absence of sharp changes in airfoil camber. One such camber morphing concept, the Fish Bone Active Camber (FishBAC) device, has shown significant aerodynamic benefits when compared to a flap. In this work, a quasi-two-dimensional wind-tunnel test was performed to investigate the aerodynamic performance of a FishBAC device and compare it to a trailing-edge plain flap. A combination of quasi-steady force balance and wake rake pressure measurements was used to determine aerodynamic force coefficients. These measurements are complemented by a flow visualization study performed using particle image velocimetry, allowing for comparison of the near-field wakes in terms of size and vortical structure. Additionally, displacement measurements were performed on the FishBAC to track deformed shapes under aerodynamic loads. Results show that the FishBAC achieves greater than a 50% improvement in lift-to-drag ratio for moderate to high lift coefficients where the device is significantly deflected and an at least 16% higher lift-to-drag ratio at all lift coefficients, even when the device deflections are low.