Computational Analysis of a Microtab-Based Aerodynamic Load Control System for Rotor Blades

Standish, Kevin; Dam, C. P. van

doi:10.4050/1.3092861

Cited by 30 publications

(17 citation statements)

References 26 publications

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“…Additionally, they investigated the effect of chordwise positioning of the GF, showing that increased upstream positioning enlarges the hysteresis loop, degrades the lift enhancement, increases drag, and decreases the nose-down pitching moment. Similar limits were found also in [10,14,28,29]. Matalanis et al [30] carried out two-and three-dimensional simulations, together with experimental measurements, on a VR-12 section equipped with a deployable GF.…”

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confidence: 50%

“…Experiments conducted on airfoils equipped with GFs highlighted the capability of these devices to significantly increase lift without severe drawbacks in terms of drag increment [3][4][5][6][7][8][9][10]. Several numerical computations have investigated the behavior of GFs [9,[11][12][13][14][15]. These studies highlighted how such movable devices allow to increase the lift, and in particular the maximum lift and the lift to drag ratio.…”

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confidence: 99%

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Linear Reduced-Order Model for Unsteady Aerodynamics of an L-Shaped Gurney Flap

Motta

Quaranta

2015

Journal of Aircraft

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Analysis of ballistic capture orbits in Sun–planet systems is conducted in this paper. This mechanism utilizes purely gravitational forces, and may occur in non-Keplerian regimes. Ballistic capture orbits are generated by proper manipulation of sets of initial conditions that satisfy a simple definition of stability. Six Sun–planet systems are considered, including the inner planets, Jupiter, and Saturn. The role of planets orbital eccentricity, their true anomaly, and mass ratios is investigated. Moreover, the influence of the post-capture orbit in terms of inclination and orientation is also assessed. Analyses are performed from qualitative and quantitative perspective. The quality of capture orbits is measured by means of the stability index, whereas the capture ratio gives information on their statistical occurrence. Some underlying principles on the selection of the dynamical model, the initial true anomaly, and inclination are obtained. These provide a reference for practical cases

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confidence: 99%

Linear Reduced-Order Model for Unsteady Aerodynamics of an L-Shaped Gurney Flap

Motta

Quaranta

2015

Journal of Aircraft

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“…The MT height relative to the chord length measured in percentage is 1%c, 1.5%c and 2%c. These series of cases has been designed according to the previous studies of Standish et al [32], Mayda et al [26] and Yen et al [21], where the maximum translation was estimated in the order of the boundary layer thickness at the device position: 1-2% of the chord length and the optimal location for a lower surface tab in terms of lift and drag was found to be around 95% of c. The MTs are placed on the pressure surface and have been studied for ten different angles of attack, from 0 • to 9 • . The combination of all these positions for the MTs gives 120 different cases to study (Ayerdi-Zaton et al [33]).…”

Section: Microtab Lay-outmentioning

confidence: 99%

Microtab Design and Implementation on a 5 MW Wind Turbine

et al. 2017

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Microtabs (MT) consist of a small tab placed on the airfoil surface close to the trailing edge and perpendicular to the surface. A study to find the optimal position to improve airfoil aerodynamic performance is presented. Therefore, a parametric study of a MT mounted on the pressure surface of an airfoil has been carried out. The aim of the current study is to find the optimal MT size and location to increase airfoil aerodynamic performance and to investigate its influence on the power output of a 5 MW wind turbine. Firstly, a computational study of a MT mounted on the pressure surface of the airfoil DU91W(2)250 has been carried out and the best case has been found according to the largest lift-to-drag ratio. This airfoil has been selected because it is typically used on wind turbine, such as the 5 MW reference wind turbine of the National Renewable Energy Laboratory (NREL). Second, Blade Element Momentum (BEM) based computations have been performed to investigate the effect of the MT on the wind turbine power output with different wind speed realizations. The results show that, due to the implementation of MTs, a considerable increase in the turbine average power is achieved.

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“…Finally, the surface could be mounted near the trailing edge as a spoiler (Scott et al, 1997). This has a similar effect as microtabs (Standish andvan Dam, 2005, Mayda et al, 2005), which are already under investigation for load control on wind …”

Section: Implementation On Wind Turbinesmentioning

confidence: 94%

A high-rate shape memory alloy actuator for aerodynamic load control on wind turbines

Lara-Quintanilla

Hulskamp

Bersee

2013

Journal of Intelligent Material Systems and Structures

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This paper discusses the development of a high rate shape memory alloy (SMA) driven actuator. The concept of the actuator was developed to act as aerodynamic load control surface on wind turbines. It was designed as a plate or beam-like structure with prestrained SMA wires embedded off its neutral axis. Moreover, the SMA material was embedded in channels through which air was forced to actively cool the wires when the recovery load was to be released. Wires were implemented on both sides of the neutral axis to deflect the beam in both directions. Thermal analysis of the cooling channels showed that they increased the cooling up to tenfold in comparison to the same set-up without forced convection. Subsequently a fuzzy logic controller was designed to control the thermo-mechanical system. The inputs were the error between the deflection and the set point, the value of the set point and the time derivative of the set point. The output consisted of two signals to the valves that controlled the flow through the channels and a signal heating signal that was split to both sets of wires, depending on its sign. The controller was tested on an antagonistic set-up, through which a similar thermo-mechanic behaviour as with the actuator was obtained, but eliminating the beam dynamics. The results were satisfactory; an actuation bandwidth of 1Hz was attained. Subsequently, the controller was tested on the actuator. With increasing actuation frequency, until 0.6Hz a relatively small error between the set point and the actual deflection was observed. Above that frequency the error increased, but also the sinusoidal response was lost. This is believed to be due to snap-through behaviour around the neutral position of the actuator. This was substantiated by the apparent inability of the actuator to track the set point around the neutral position in tracking a composite sinusoidal set point.

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Computational Analysis of a Microtab-Based Aerodynamic Load Control System for Rotor Blades

Cited by 30 publications

References 26 publications

Linear Reduced-Order Model for Unsteady Aerodynamics of an L-Shaped Gurney Flap

Linear Reduced-Order Model for Unsteady Aerodynamics of an L-Shaped Gurney Flap

Microtab Design and Implementation on a 5 MW Wind Turbine

A high-rate shape memory alloy actuator for aerodynamic load control on wind turbines

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