An Innovative Design of a Microtab Deployment Mechanism for Active Aerodynamic Load Control

Tsai, Kuo-Chang; Pan, Cheng‐Tang; Cooperman, Aubryn; Johnson, Scott J.; Dam, C. P. van

doi:10.3390/en8065885

Cited by 23 publications

(16 citation statements)

References 12 publications

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“…Tsai et al's work [11] shows that the Gurney flap mainly changes the effective camber of the airfoil, which has a significant impact on the small AoA. Hence, the range of the angle of attack for subsequent numerical simulations is -2°~16°.…”

Section: Resultsmentioning

confidence: 99%

“…Gurney flaps have been widely used and studied in airfoil static/dynamic stall control [2][3][4][5], flutter control [6], flapping airfoil control [7], ground effects [8], and rotor blade load control [9][10][11][12][13]. In these applications, the increases in the lift and the drag are closely related to airfoils, flow conditions, and the flap geometry.…”

Section: Introductionmentioning

confidence: 99%

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Effect of Gurney Flap Geometry on a S809 Airfoil

Hao

Gao

2019

International Journal of Aerospace Engineering

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In this paper, the effect of Gurney flap shapes on wind turbine blade airfoil S809 has been studied by numerical simulation. First, the O-type grid is used in the numerical simulation. By comparing with experimental data, such as the lift force, the drag coefficient, and the pressure distribution, the accuracy of the simulation method is validated. Second, the research on the widths of three kinds of rectangular Gurney flaps at the trailing edge of the S809 airfoil is carried out. Rectangular Gurney flaps can considerably increase the lift in both the linear and nonlinear sections, and the maximum lift coefficient can be increased by 20.65%. In addition, the drag and the pitching moment are increased. However, the width of the rectangular Gurney flap has a small impact on the lift, the drag, and the pitching moment. Finally, the effects of rectangular and triangular Gurney flaps on the aerodynamic characteristics of the S809 airfoil are compared. The results show that the triangular flaps can obtain an increase of maximum lift coefficient by 28.42%, which is better than 16.31% of the rectangular flaps.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Effect of Gurney Flap Geometry on a S809 Airfoil

Hao

Gao

2019

International Journal of Aerospace Engineering

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“…As regards the former issue, the fields of research are layout optimization [3][4][5][6][7], cooperative wind turbine control [8][9][10], and yaw active control for wake mitigation [11][12][13][14][15]. As regards the latter issue, several types of wind turbines retrofitting for power production improvement are possible: They can be aerodynamic and based on the modification of the blade profile (installation of vortex generators, passive flow control devices, Gurney flaps, and so on [16][17][18][19][20]), or they can involve the control system and deal with the management of the blade pitch [21], the rotor rpm, the cut-out wind speed, and the high wind speed cut-in (defined as the wind speed at which the wind turbine starts producing again after a gust) [22][23][24].…”

Section: Introductionmentioning

confidence: 99%

Numerical and Experimental Methods for the Assessment of Wind Turbine Control Upgrades

et al. 2018

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Megawatt-scale wind turbine technology is nowadays mature and, therefore, several technical improvements in order to optimize the efficiency of wind power conversion have been recently spreading in the industry. Due to the nonstationary conditions to which wind turbines are subjected because of the stochastic nature of the source, the quantification of the impact of wind turbine power curve upgrades is a complex task and in general, it has been observed that the efficiency of the upgrades can vary considerably depending on the wind flow conditions at the microscale level. In this work, a test case of wind turbine control system improvement was studied numerically and through operational data. The wind turbine is multi-megawatt; it is part of a wind farm sited in a complex terrain in Italy, featuring 17 wind turbines. The analyzed control upgrade is an optimization of the revolutions per minute (rpm) management. The impact of this upgrade was quantified through a method based on operational data: It consists of the study, before and after the upgrade, of the residuals between the measured power output of the wind turbine of interest and an appropriate model of the power output itself. The input variables for the model were selected to be some operational parameters of the nearby wind turbines: They were selected from the data set at disposal with a stepwise regression algorithm. This work also includes a numerical characterization of the problem, by means of aeroelastic simulations performed with the FAST software: By mimicking the pre-and post-upgrade generator rpm-generator torque curve, it is subsequently possible to estimate how the wind turbine power curve changes. The main result of this work is that the two estimates of production improvement have the same order of magnitude (1.0% of the production below rated power). In general, this study sheds light on the perspective of employing not only operational data, but also a sort of digital replica of the wind turbine of interest, in order to reliably quantify the impact of control system upgrades.

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“…Lei Zhang et al [26,27] made long-term efforts to investigate the effects of vortex generators. Some other researchers focused on microtabs [28,29] and obtained some good results. T.K.…”

Section: Introductionmentioning

confidence: 99%

Aerodynamic Performance of Wind Turbine Airfoil DU 91-W2-250 under Dynamic Stall

Zhang

Yang

et al. 2018

Applied Sciences

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Airfoils are subjected to the 'dynamic stall' phenomenon in significant pitch oscillations during the actual operation process of wind turbines. Dynamic stall will result in aerodynamic fatigue loads and further cause a discrepancy in the aerodynamic performance between design and operation. In this paper, a typical wind turbine airfoil, DU 91-W2-250, is examined numerically using the transition shear stress transport (SST) model under a Reynolds number of 3 × 10 5. The influence of a reduced frequency on the unsteady dynamic performance of the airfoil model is examined by analyzing aerodynamic coefficients, pressure contours and separation point positions. It is concluded that an increasingly-reduced frequency leads to lower aerodynamic efficiency during the upstroke process of pitching motions. The results show the movement of the separation point and the variation of flow structures in a hysteresis loop. Additionally, the spectrum of pressure signals on the suction surface is analyzed, exploring the level of dependence of pressure fluctuation on the shedding vortex and oscillation process. It provides a theoretical basis for the understanding of the dynamic stall of the wind turbine airfoil.

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An Innovative Design of a Microtab Deployment Mechanism for Active Aerodynamic Load Control

Cited by 23 publications

References 12 publications

Effect of Gurney Flap Geometry on a S809 Airfoil

Effect of Gurney Flap Geometry on a S809 Airfoil

Numerical and Experimental Methods for the Assessment of Wind Turbine Control Upgrades

Aerodynamic Performance of Wind Turbine Airfoil DU 91-W2-250 under Dynamic Stall

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