Aeroelastic model validation of an Active Trailing Edge Flap System tested on a 4.3 MW wind turbine

Active Trailing Edge Flap Systems (ATEFS) have shown promising results on reducing Wind Turbine fatigue and ultimate loads and increasing the Annual Energy Production. However, the current lack of field validation creates uncertainty in the fidelity level and accuracy of the engineering models used for the aeroelastic modeling of active flaps, and these systems actual load reduction capabilities are in question. This article describes the validation based on field data of the aeroelastic engineering models of the ATEFS developed for the BEM-based solvers HAWC2 and BHawC for the case of stationary activation of the flap. The validation is based on the field test data from a 4.3 MW Wind Turbine with one blade equipped with an ATEFS and operating in normal power production. With simulation results differing from the measurement of a max of ±3% on mean power, ±0.2 deg on mean pitch angle, ±0.1 rpm on rotor speed, and ±2% on flapwise blade loads, the study showed the HAWC2 and BHAWC aeroelastic ATEFS models provide a reliable and precise estimation of the impact of the ATEFS on the Wind Turbine for the case of stationary activation of the flap.