This study focuses on an active strategy for unsteady-load control by means of a trailing-edge flap. Experiments on a 2D pitching and heaving NACA 0018 airfoil with an actuated trailing-edge flap are performed at a reduced frequency κ = 0.1 in a free-stream flow with Re = 1.3 × 10⁵. The model is equipped with 24 differential pressure transducers to provide with the time-resolved distribution of the pressure difference between pressure and suction sides. Results show that an actuated flap significantly decreases the magnitude of unsteady loads. A reduced order model of the flap effect on the loads is proposed. The loads are estimated by adding the contribution of the clean wing with the flap one. This model can be applied to unsteady loads for both attached flow and dynamic stall conditions, constituting an effective control strategy for dynamic loads, if the airfoil transition location is properly controlled.

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Dynamic stall limits the operative life of rotors, due to a periodic occurrence of force and moment peaks that can lead to blade structural-failure. The aim of this study is to investigate the possibility of controlling cyclic forces on wind turbine blades by means of Trailing Edge Flaps. The periodic motion of a rotor blade is reproduced by a 2D wing pitching and plunging in a free-stream flow at 푹풆=ퟏ.ퟑ× ퟏퟎퟓ. The wing is equipped with 50 pressure taps able to provide with a time-resolved distribution of the pressure on the wing. A trailing-edge flap is installed in the wing and actuated with respect to the wing motion. Flap actuations in phase opposition to the rotor motion are found to maximize the lift integral over the period while minimizing the load fluctuations over time. @en