Active Wing Flutter Suppression Using a Trailing Edge Flap

Borglund, Dan; Kuttenkeuler, Jakob

doi:10.1006/jfls.2001.0426

Cited by 57 publications

(26 citation statements)

References 24 publications

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“…It appears the 2nd blade flap mode and 1st torsion mode are converging which would see them merge somewhere between 3Hz and 4Hz to cause Flutter. This value is in the vicinity of values found from other studies with similar sized blades and properties 3,13 . This result gives some confidence in the methodology used to determine the Flutter limits.…”

supporting

confidence: 60%

“…Therefore, the dynamics occurring near the Flutter speed were examined in the frequency domain in an attempt to verify at which frequency the flap and torsion modes are merging to cause Flutter, and whether the 1 st or 2 nd flap mode is the cause. In other studies on Flutter 13 , it is stated the second flapwise mode is usually interacting with the torsion mode because of the relatively high torsional stiffness compared to the "soft" first flapwise mode. The system spectral response is analysed using a case with a mean wind speed of 15ms -1 .…”

mentioning

confidence: 98%

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Suppression of Classical Flutter Using a 'Smart Blade'

Politakis

Haans

Bussel

2008

46th AIAA Aerospace Sciences Meeting and Exhibit

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Future horizontal axial wind turbines that approach the 10MW capacity will have a rotor diameter somewhere in the order of 170m. Their loads could be much higher and their blades more flexible compared to current multi-MW wind turbines, most probably resulting in aeroelastic instabilities not commonly seen in the machines of today. The likely design drivers for future 10MW+ wind turbines are fatigue life and aeroelastic stability. To help improve the fatigue life and the aeroelastic stability, load control could be applied to future wind turbines. This paper concerns the load control concept of an actuated trailing edge flap (TEF), focusing on the effects they have on the aeroelastic stability of a blade. In particular, the two degree of freedom Flap-Torsion Flutter instability-Classical Flutter-is studied.

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supporting

confidence: 60%

mentioning

confidence: 98%

Suppression of Classical Flutter Using a 'Smart Blade'

Politakis

Haans

Bussel

2008

46th AIAA Aerospace Sciences Meeting and Exhibit

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“…Aircraft wings are susceptible to an oscillatory instability at high speeds, called flutter. Flutter mitigation strategies have evolved in the recent years to use trailing edge flaps for suppressing vibrations [1], [2]. The resulting control problem involves the stabilization of the coupled bending-torsion dynamics.…”

Section: Introductionmentioning

confidence: 99%

Output feedback stabilization of linear PDEs with finite dimensional input-output maps and Kelvin-Voigt damping

Paranjape

Chung

2015

2015 54th IEEE Conference on Decision and Control (CDC)

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Abstract-In this paper, we consider systems of partial differential equations with a finite relative degree between the input and the output. In such systems, an output feedback controller can be constructed to regulate the output with the desired convergence properties. Although the zero dynamics are infinite dimensional, we show that the controller alters the boundary conditions in such a way that it leads to a predictable expansion in the stable operating envelope of the system. Moreover, the expansion of the stable envelope depends only on the boundary conditions and the structure of the PDE, and is independent of the system parameters. The methodology is extended to output tracking and time-varying forcing functions as well. The phenomenon investigated in the paper is quite unique to partial differential equations and without any parallel in systems of ODEs.

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“…The concept of using flaps for control is not new; it has been used in the aeronautics industry for flutter suppression and buffet loads alleviation, where flaps respond to the wing's oscillatory motion, as seen, for example in Triplett (1972); Triplett et al (1973); Roger et al (1975); Karpel (1982); Borglund and Kuttenkeuler (2002); Burnett et al (2010). The main advantage of feedback control using controllable flaps relative to traditional structural changes is the possibility of raising significantly the critical speed for flutter along with considerable potential cost advantages.…”

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confidence: 99%

Buffet loading, dynamic response and aerodynamic control of a suspension bridge in a turbulent wind

Zhao

Gouder

Graham

et al. 2016

Journal of Fluids and Structures

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This paper describes experiments relating to the buffet response and control of a section of a long-span suspension bridge deck elastically mounted as part of a wind tunnel experiment. The bridge section is subject to grid generated flow turbulence. Two grids are used -one is a standard biplanar grid, while the second is a new design that provides larger turbulence length scales. The buffet response results are compared with admittances calculated using unsteady, three-dimensional, lifting-surface theory that extends standard two-dimensional Sears' theory. The bridge deck heave and pitch responses are predicted with comparisons made with wind tunnel measurements. In order to suppress buffeting, and increase the deck's critical flutter speed, the deck model is fitted with controllable leading-and trailing-edge flaps. Two sets of passive controllers, which use the flap angles as the control inputs, are demonstrated and evaluated for their capability to suppress the buffet response of the deck and increase its critical flutter speed. The first set of controllers sense the deck's position (pitch angle and heave, or pitch angle alone), whilst the second set (which are mechanical controllers) sense the vertical velocity of the flap hinge points. The control system design problem is solved as a mixed H 2 /H ∞ optimisation problem. The wind tunnel experPreprint submitted to Fluids and Structures June 14, 2016 iments show that these control systems can reduce considerably the deck's buffet response, whilst simultaneously increasing its critical flutter speed.

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Active Wing Flutter Suppression Using a Trailing Edge Flap

Cited by 57 publications

References 24 publications

Suppression of Classical Flutter Using a 'Smart Blade'

Suppression of Classical Flutter Using a 'Smart Blade'

Output feedback stabilization of linear PDEs with finite dimensional input-output maps and Kelvin-Voigt damping

Buffet loading, dynamic response and aerodynamic control of a suspension bridge in a turbulent wind

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