Initial Studies of an Oscillating Airfoil for Characterizing Fence Actuators for Flutter Suppression

Preliminary experiments have been conducted to characterize ∞ow behavior past stationary and oscillating airfoils for assessment of fence actuators. In particular, the flxed fence performance on a NACA-23012 airfoil has been examined. Fences and other actuators (eg. synthetic jets) have been used successfully in the past for active ∞ow control applications and are attractive alternatives to current methods used for ∞utter suppression. Experiments were conducted for characterization of stationary and oscillating airfoils with and without a fence. Results from the baseline characterization of the oscillating airfoil showed that the pressure distribution on the wing for up-cycle and down-cycle is asymmetric about the peak and can produce complicated lag and lead efiects. Experiments with a static fence on stationary and oscillating airfoils showed that the static fence efiectively acts like a spoiler by producing a substantial suction peak and pressure rise downstream and upstream respectively. It was also observed that the disturbances produced from the fence remained almost the same for stationary and oscillating airfoil. Results from these experiments will be used to develop, implement and assess the performance of an oscillating fence actuator on stationary and oscillating airfoils.

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