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Comparison of numerical and experimental results for NACA64-618 airfoil section for the lift and drag coefficient value with respect to angle of attack: (a) C l versus a and (b) C d versus a Fig. 5 Lift coefficient C l and drag coefficient C d versus angle of attack a curves for different actuation angles: (a) C l versus a and (b) C d versus a
Source publication
This paper focuses on load mitigation by implementing controllable trailing-edge slotted flaps on the blades of an offshore wind turbine (OWT). The benchmark NREL 5MW horizontal axis OWT is subjected to coupled stochastic aerodynamic-hydrodynamic analysis for obtaining the responses. The OWT is supported on three different fixed-bottom structures s...
Citations
... Chen et al. (2019) designed a passive load control technique by using backward swept blades and explored its potential capability of mitigating load variations in the shear wind. Thakur et al. (2018) focused on load mitigation by implementing controllable trailingedge slotted flaps on the blades of an offshore wind turbine and up to 20% load reduction was achieved. Bottasso et al. (2016) conducted an investigation on passive mitigation of loads on wind turbines. ...
Wind turbine blades are adjusted in real-time according to the wind conditions and blade deformations to improve power generation efficiency. It is necessary to predict and reduce the aeroelastic deformations of wind turbine blades. In this paper, the equivalent model of the blade is established by the finite element method (FEM), and the aerodynamic load of the blade is evaluated based on the blade element momentum (BEM) theory. The aeroelastic coupling model is established, in which the bending-torsion coupling effect of the blade is taken into account. The steady and dynamic aeroelastic deformations are calculated. The influences of the blade section's shear centre position and the blade's sweepback design on the deformations are analyzed. The novel approaches of reducing the twist angle of the blade by changing the shear centre position and sweepback of the blade are presented and proven to be feasible.
... Aerodynamically active devices, showing more effectiveness with spanwise controls have gained significant research interest over the last decade as it ensures stability and reduces the fatigue experienced in the wind turbines. Several numerical investigations have been done, i.e., the modelling and optimization by including blade trailing edge flaps with the aim to reduce the cost of energy [6][7][8]. These investigations have shown the significance of the aerodynamic devices in power capture optimization. ...
Keywords: Offshore wind turbine Soil-structure interaction Non-linear dynamical analysis Blade slotted flaps Probabilistic analysis A B S T R A C T This work attempts to investigate the load mitigation effects on foundations of NREL 5-MW offshore wind turbine (OWT) supported on fixed structures using blade trailing edge flaps. The analysis is subjected to turbulent wind and irregular wave loads. The offshore wind turbine is simulated for five met-ocean conditions for Indian scenario, covering operational to the parked region of turbine. Sea states being stochastic, the responses are obtained using average of Monte Carlo simulations. The blade element momentum theory is used to obtain the aerodynamic loads by modelling in a multi-body framework while the hydrodynamic and geotechnical analysis are performed in a finite element framework. Soil-structure interaction is modelled using nonlinear Winkler spring model along the length of the pile. The trailing edge flaps are numerically implemented through a dynamic link library into the aerodynamic program. Loose sandy soils with uniform density is considered for analysis. The results bring out the importance of including blade trailing edge flaps in OWT studies with significant response reduction (2.1-16.0%) for designing pile foundations.
