Print Email Facebook Twitter Fluctuations of angle of attack and lift coefficient and the resultant fatigue loads for a large Horizontal Axis Wind turbine Title Fluctuations of angle of attack and lift coefficient and the resultant fatigue loads for a large Horizontal Axis Wind turbine Author Rezaeiha, Abdolrahim (Eindhoven University of Technology) Balbino dos Santos Pereira, R. (TU Delft Wind Energy) Kotsonis, M. (TU Delft Aerodynamics) Date 2017-12-01 Abstract Unsteady loads are a major limiting factor for further upscaling of HAWTs considering the high costs associated to strict structural requirements. Alleviation of these unsteady loads on HAWT blades, e.g. using active flow control (AFC), is of high importance. In order to devise effective AFC methods, the unsteady loading sources need to be identified and their relative contribution to the load fluctuations experienced by blades needs to be quantified. The current study investigates the effects of various atmospheric and operational parameters on the fluctuations of α and CL for a large HAWT. The investigated parameters include turbulence, wind shear, yawed inflow, tower shadow, gravity and rotational imbalances. The study uses the DTU's aeroelastic software HAWC2. The study identifies the individual and the aggregate effect of each source on the aforementioned fluctuations in order to distinguish the major contributing factors to unsteady loading. The quantification of contribution of each source on the total fatigue loads reveals >65% of flapwise fatigue loads is a result of turbulence while gravity results in >80% of edgewise fatigue loads. The extensive parametric study shows that the standard deviation of CL is 0.25. The results support to design active load control systems by highlighting the magnitude of CL and α variations experienced by HAWTs, and thus the dCL that needs to be delivered by an AFC system. Subject Active flow controlAngle of attack and lift coefficientFatigueFluctuationsHorizontal Axis Wind turbine (HAWT)TurbulenceUnsteady load control To reference this document use: http://resolver.tudelft.nl/uuid:5164633d-582d-440f-922d-7c3d9b2ce81f DOI https://doi.org/10.1016/j.renene.2017.07.101 ISSN 0960-1481 Source Renewable Energy, 114, 904-916 Part of collection Institutional Repository Document type journal article Rights © 2017 Abdolrahim Rezaeiha, R. Balbino dos Santos Pereira, M. Kotsonis Files PDF 1_s2.0_S0960148117307280_main.pdf 3.39 MB Close viewer /islandora/object/uuid:5164633d-582d-440f-922d-7c3d9b2ce81f/datastream/OBJ/view