TRANSPORT AIRCRAFT WING INVESTIGATIONS AIMED ON WAKE VORTEX IMPACT BY OSCILLATING FLAPS

The effect of oscillating trailing edge flaps on the wake vortex system of a generic transport aircraft is investigated. The half model presents a high lift configuration (droop nose, advanced dropped hinge flaps) of a generic transport aircraft. For constant temperature anemometry (CTA) measurements, experiments are carried out in the Göttingen-type low-speed wind tunnel C of the Chair of Aerodynamics and Fluid Mechanics of the Technical University of Munich. The experiments are performed at low speed wind tunnel conditions with a Reynolds number of Re = 0.5 · 10⁶ and a Mach number of Ma = 0.07. The wake vortex system of the configuration is captured at cross flow planes perpendicular to the freestream direction at nondimensional distances based on the wing span b of x/b = (0.064, 3, 6). A baseline configuration with statically deflected flaps is compared to configurations with actuated flaps performing harmonic motions. Both different actuation frequencies k = (0.04, 0.08, 0.16) and flap amplitudes ∆δ = (2.5^◦, 5^◦) are investigated at x/b = 6. It can be shown that a significant disturbance can be imposed already in the extended near field of the wake vortex system for both flap amplitudes, propagating downstream. In addition, all introduced frequencies and higher harmonics are measurable at x/b = 6 intended to trigger and enhance the development of wake vortex instabilities fostering wake vortex decay.