Investigation into the Possibility of Flap-Lag-Stall Flutter

Holierhoek, Jessica G.

doi:10.2514/6.2007-211

Cited by 7 publications

(7 citation statements)

References 2 publications

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“…This, in combination with stalled flow can result in aeroelastic instabilities [28]. The damage resulted from severe aeroelastic instabilities producing longitudinal cracks on the flexible part of the blade near the root.…”

Section: Mechanical Modelingmentioning

confidence: 99%

Offshore Wind Energy System with DC Transmission Discrete Mass: Modeling and Simulation

Seixas

Melício

Mendes

2016

Electric Power Components and Systems

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Section: Mechanical Modelingmentioning

confidence: 99%

Offshore Wind Energy System with DC Transmission Discrete Mass: Modeling and Simulation

Seixas

Melício

Mendes

2016

Electric Power Components and Systems

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“…Because the effective angle of attack on the wind turbine blade is not sufficiently small, the sin ø and cos ø can be treated as the (−U N /U) and (U T /U), respectively. After substituting each force terms into Equations (11,12) and regrouping terms, the rearranged equations can be expressed as follows:…”

Section: Modification Of Greenberg's Extension Of Theodorsen's Strip mentioning

confidence: 99%

“…For these reasons, the aeroelastic problems of wind turbine blades have a significant impact on their dynamic stability. The blade pitch-flap flutter [2][3][4][5], stall-induced vibration [6][7][8][9][10][11], rotor-shaft whirl [12,13], and aeromechanical instability [14,15] are all examples of known instabilities for rotary wings (e.g., modern wind turbines and helicopter rotors). These aeroelastic instabilities or even marginal stabilities, can lead to rapid destructive failure or limit-cycle oscillation [16].…”

Section: Introductionmentioning

confidence: 99%

Torsional Stiffness Effects on the Dynamic Stability of a Horizontal Axis Wind Turbine Blade

et al. 2013

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Aeroelastic instability problems have become an increasingly important issue due to the increased use of larger horizontal axis wind turbines. To maintain these large structures in a stable manner, the blade design process should include studies on the dynamic stability of the wind turbine blade. Therefore, fluid-structure interaction analyses of the large-scaled wind turbine blade were performed with a focus on dynamic stability in this study. A finite element method based on the large deflection beam theory is used for structural analysis considering the geometric nonlinearities. For the stability analysis, a proposed aerodynamic approach based on Greenberg's extension of Theodorsen's strip theory and blade element momentum method were employed in conjunction with a structural model. The present methods proved to be valid for estimations of the aerodynamic responses and blade behavior compared with numerical results obtained in the previous studies. Additionally, torsional stiffness effects on the dynamic stability of the wind turbine blade were investigated. It is demonstrated that the damping is considerably influenced by variations of the torsional stiffness. Also, in normal operating conditions, the destabilizing phenomena were observed to occur with low torsional stiffness. OPEN ACCESSEnergies 2013, 6 2243 Keywords: blade element momentum method; dynamic stability; fluid-structure interaction; Greenberg's extension of Theodorsen's strip theory; wind energy

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“…Stall flutter can occur on aircraft tails, highly flexible wings, helicopter blades 1 and wind turbines. 2,3 Although some of the earliest stall flutter experiments were carried out in the 1940s, 4 the bulk of the related research has concentrated on dynamic stall during the second half of the twentieth century. One of the first extensive experimental investigations of stall flutter was the NASA Benchmark Models Program.…”

Section: Introductionmentioning

confidence: 99%

Computational Considerations for the Prediction of Stall Flutter

Watrin¹,

Dimitriadis²,

Perry³

et al. 2012

53rd AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials Conference

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A solver has been developed within the OpenFoam framework to compute large amplitude motion of two-dimensional rigid configurations. The results obtained with this code were successfully validated on rigid airfoils at static and dynamic conditions, as well as correlated with experimental data and numerical solutions from similar unsteady solvers. The results demonstrated that while current computational methods are able to predict the self-sustained oscillations characterizing a pitch-dominated stall flutter, including energy transfer, improvements are needed. The influence of grid, temporal integration, turbulence modeling, and flow equations is examined for the stall flutter starting solution of dynamic stall. Nomenclaturestream Mach number N Grid size in number of cells N ref Reference grid size in number of cells N sub−iters Number of sub-iterations per time step Re Reynolds number t Time, seconds T Period of cycle, seconds V ∞ Free stream velocity, m/s α Angle of attack, degrees α 0 Mean angle of attack, degrees α 1 Amplitude of angle of attack, degrees ω Frequency of oscillation, radians/second

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Investigation into the Possibility of Flap-Lag-Stall Flutter

Cited by 7 publications

References 2 publications

Offshore Wind Energy System with DC Transmission Discrete Mass: Modeling and Simulation

Offshore Wind Energy System with DC Transmission Discrete Mass: Modeling and Simulation

Torsional Stiffness Effects on the Dynamic Stability of a Horizontal Axis Wind Turbine Blade

Computational Considerations for the Prediction of Stall Flutter

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