Active Aerodynamic Control of Wind Turbine Blades with High Deflection Flexible Flaps

Abstract

The implementation of an innovative aerodynamic control technique in wind turbines is a point under extensive investigation since the conventional wind turbine blade technology is reaching its limits. Almost all the eort of the wind turbine industry in the eld of aerodynamics is related to the development of blades which oer better performance, increased reliability and faster control of larger wind turbines. Currently, however, most of the research eort is focusing on the implementation of aerodynamic elements for dynamic load alleviation during wind turbine operation rather than rotor stall control or even more the complete wind turbine power regulation which is the ultimate target of the current project. The current document presents the test process, methodology and results of wind tunnel test campaigns on the investigation of the exible ap conguration as a possible means of aerodynamic control of wind turbines. The test campaign took place at the HFI/TU Berlin wind tunnel. Measurements were performed with a model of the DU96W180 airfoil as well as with the modied-DU96W180 test airfoil section equipped with the exible ap assembly in ow with Reynolds number Re equal to 1,300,000. The The exible ap was tested in various positive and negative deections in order to extract its complete operational curve. The results showed signicant inuence on both lift and drag as well as strong variations on the pitch behavior of the wing. The paper also discusses the possible benets of the integration of exible ap systems in wind turbine blade structures.