Three-dimensional numerical simulations of vortex-induced vibrations of tapered circular cylinders

Kaja, Kalyani; Zhao, Ming; Xiang, Yang; Cheng, Liang

doi:10.1016/j.apor.2016.08.004

Cited by 18 publications

(5 citation statements)

References 32 publications

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“…This conclusion was also drawn, for instance, with studies that focused on end-effects (Williamson, 1989;K€ onig et al, 1992). More recently, numerical studies have also captured the presence of phase dislocations, both for uniform cylinders (Braza et al, 2001;Aarnes et al, 2018) and for tapered cylinders (Kaja et al, 2016). Moving closer to the present application, Yang et al (2013) reported simulations of a flat plate at low inclination angles, linking the appearance of phase dislocations with the distinct characteristic frequencies of the normal shedding and the parallel shedding.…”

Section: F Relation Between the Transferred Power And The Wakementioning

confidence: 62%

Vibrations of wind turbine blades in standstill: Mapping the influence of the inflow angles

et al. 2022

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The present investigation used numerical simulations to study the vibrations of a wind turbine blade in standstill. Such vibrations are presumed to affect horizontal axis wind turbine designs and can jeopardize the structural integrity of the machine. The applied numerical methods relied on a fluid–structure interaction (FSI) approach, coupling a computational fluid dynamics (CFD) solver with a multibody finite-element structural solver. A 96-m-long wind turbine blade was studied for a large parametric space, accounting for the variation of both pitch and inclination. The inclination was defined as the angle between the freestream velocity and the cross-sectional plane at the root, allowing for the introduction of a flow component in the spanwise direction. The pitch variation corresponded to the rotation of the inflow around the spanwise axis, steering the angles of attack seen by the airfoils. Two regimes of vibrations were characterized, depending on the considered range of the inclination angle. For high inclinations, the pitch angles leading to vibrations clustered around a particular region of the parametric space, and the appearance of large oscillations was accompanied by the synchronization of the loading with the frequency of motion. At low inclination angles, the mechanism triggering vibrations was relatively similar, even if the excitation spectrum was richer, and the critical pitch angles seemed to be more scattered. Regardless of the inflow, the problem was highly three-dimensional, and several complex flow phenomena such as oblique shedding and phase dislocations were identified.

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Section: F Relation Between the Transferred Power And The Wakementioning

confidence: 62%

Vibrations of wind turbine blades in standstill: Mapping the influence of the inflow angles

et al. 2022

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“…Noticeably, the results obtained are only representative of the current case under consideration. For a rotor azimuth of 0º it is expected that the critical blade driving power injection will be the one pointing up and being its critical wind speed lower than for the blades at 60º and 300º (as described in [7] or [11]) and similar to the critical wind speed of the tower, thus changing the range at which oscillations might be expected. The analysis of this further configuration is out of the scope of the current study.…”

Section: Rotor and Tower Power Injection For Reference Casementioning

confidence: 99%

Impact of rotor blade aerodynamics on tower vortex induced vibration of modern wind turbines

Ludlam,

Jacobs,

Ahmed

2024

J. Phys.: Conf. Ser.

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Modern wind turbines in standstill or idling could experience vortex induced vibrations (VIV); the origin of these vibrations is either shedding from the wind turbine blade referred to as blade VIV or shedding from tower termed as tower (or turbine) VIV. When the whole structure of the wind turbine is considered and the blades are pitched out, the dominant 1st order mode for blade deformation in edgewise direction leads to negligible motion of the tower top, while when the whole turbine vibrates with first tower mode, blades also undergo significant periodic translations and deformations. In this study, forced motion is used to study the impact of aerodynamic damping due to rotor moving with 1st tower mode. In the literature no comprehensive work is available to characterize the impact of blades aerodynamics in the turbine mode either using systematic tests or high-fidelity computational fluid dynamics (CFD). In this article high-fidelity numerical simulations are performed to compute the power injections from the rotor blades when the turbine moves in 1st tower mode. Depending on the inflow angle and the azimuthal position, blades can inject significant power. Thus, the estimated damping from tower-only empirical models could severely underestimate the total aerodynamic power if the power injection from the rotor is neglected.

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“…In Kaja et al [13], the wake of tapered cylinders for certain inflow conditions accounted for a combination of two distinct shedding patterns (i.e., 2S and 2P). The lock-in regime of the reduced velocity for a tapered cylinder was found to be wider than that of a uniform cylinder.…”

Section: Assumptions and Modelling Detailsmentioning

confidence: 99%

Assessment of Vortex Induced Vibrations on wind turbines

Manolas

Chaviaropoulos²,

Riziotis

2022

J. Phys.: Conf. Ser.

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Modern wind turbines are prone to Vortex Induced Vibrations (VIV). In the present work, an engineering semi-empirical framework is proposed that assesses VIV aero-elastic instabilities of wind turbine configurations. The procedure employs engineering tools relying on airfoil polars. It uses the state-of-the-art aero-elastic tool hGAST along with the EUROCODE VIV framework for steel structures extended to wind turbine configurations. The aero-elastic tool provides the missing modal input data (i.e. modal frequencies, total structural plus aerodynamic modal damping and modeshapes) to evaluate the semi-analytical expressions of the displacement and load amplitudes. Numerical results for single- and two-bladed configurations of the NREL 5MW Reference Wind Turbine (RWT) during assembly are presented, assessing turbine loads under the most unfavourable VIV scenarios examined.

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Three-dimensional numerical simulations of vortex-induced vibrations of tapered circular cylinders

Cited by 18 publications

References 32 publications

Vibrations of wind turbine blades in standstill: Mapping the influence of the inflow angles

Vibrations of wind turbine blades in standstill: Mapping the influence of the inflow angles

Impact of rotor blade aerodynamics on tower vortex induced vibration of modern wind turbines

Assessment of Vortex Induced Vibrations on wind turbines

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