Wind‐induced fatigue of large HAWT coupled tower–blade structures considering aeroelastic and yaw effects

Ke, Shitang; Wang, Tongguang; Ge, Yaojun; Wang, Hao

doi:10.1002/tal.1467

Cited by 17 publications

(6 citation statements)

References 30 publications

(37 reference statements)

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“…The following effects have been simulated: Wind shear: depending on the surface conditions on site, a nonuniform wind profile leads to an increase in wind speed with height; hence, the blade encounters different wind speeds across the rotation angle

. Wind speed was simulated as

, with

being the wind speed at hub height H ,

being the empirical wind shear exponent set to

in the simulation, and

being the effective blade height at rotation angle

and blade radius R [ 11 ]. Gravity: gravity counteracts bending due to wind load in case of a downwards movement of the blade and enhances bending due to wind load in case of an upwards movement of the blade.…”

Section: Simulationmentioning

confidence: 99%

“…Wind shear: depending on the surface conditions on site, a nonuniform wind profile leads to an increase in wind speed with height; hence, the blade encounters different wind speeds across the rotation angle α t . Wind speed was simulated as V(z) = V H • (z/H) φ , with V H being the wind speed at hub height H, φ being the empirical wind shear exponent set to 0.2 in the simulation, and z = h 0 + R • cos(α t ) being the effective blade height at rotation angle α t and blade radius R [11]. 2.…”

Section: Alternate Bending Effectsmentioning

confidence: 99%

“…While maximum deflection in yaw conditions occurred at about 90 and 270 azimuth angle, the authors could also show that results varied for different solving algorithms. Additionally, Ke et al [ 11 ] investigated wind-induced fatigue of large turbines in periodic wind effects. Furthermore, Liew et al [ 12 ] studied individual pitch control (ICP) to prevent alternate bending by guiding blades along a preset trajectory but did not consider feasible sensor solutions for measuring tip deflection yet.…”

Section: Introductionmentioning

confidence: 99%

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Moving Accelerometers to the Tip: Monitoring of Wind Turbine Blade Bending Using 3D Accelerometers and Model-Based Bending Shapes

Loss

Bergmann

2020

Sensors

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Increasing the length of wind turbine blades for maximum energy capture leads to larger loads and forces acting on the blades. In particular, alternate bending due to gravity or nonuniform wind profiles leads to increased loads and imminent fatigue. Therefore, blade monitoring in operation is needed to optimise turbine settings and, consequently, to reduce alternate bending. In our approach, an acceleration model was used to analyse periodically occurring deviations from uniform bending. By using hierarchical clustering, significant bending patterns could be extracted and patterns were analysed with regard to reference data. In a simulation of alternate bending effects, various effects were successfully represented by different bending patterns. A real data experiment with accelerometers mounted at the blade tip of turbine blades demonstrated a clear relation between the rotation frequency and the resulting bending patterns. Additionally, the markedness of bending shapes could be used to assess the amount of alternate bending of the blade in both simulations and experiment.s The results demonstrate that model-based bending shapes provide a strong indication for alternate bending and, consequently, can be used to optimise turbine settings.

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. Wind speed was simulated as

, with

being the wind speed at hub height H ,

being the empirical wind shear exponent set to

in the simulation, and

being the effective blade height at rotation angle

Section: Simulationmentioning

confidence: 99%

Section: Alternate Bending Effectsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Moving Accelerometers to the Tip: Monitoring of Wind Turbine Blade Bending Using 3D Accelerometers and Model-Based Bending Shapes

Loss

Bergmann

2020

Sensors

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“…For example, the integral length of the velocity, the turbulence intensity, the mean velocity, and the spectrum of the velocity is assumed to be constants at a certain height. Then, adopting some mathematical methods, such as superposition harmonic method, the wind with turbulence can be generated. However, in the wake of the wind turbine, the integral length of the velocity, the turbulence intensity, the mean velocity, and the spectrum of the velocity varies not only in the vertical direction but also in the lateral direction.…”

Section: Introduction To Aowtmentioning

confidence: 99%

Numerical simulations of fatigue loads on wind turbines operating in wakes

Liu

Ishihara

et al. 2020

Wind Energy

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Wake effects increase the fatigue loads on wind turbines in operation. However, the wake flow is considerably different from the traditional boundary layer flow, and poses many challenges in determining the fatigue loads on wind turbines operating in a wake. Therefore, in the present study, the actuator-line model was adopted to numerically simulate the wake flow and an in-house code named AOWT, which is based on a generalized coordinate method, was developed for analyzing the dynamics of wind turbines under an arbitrary distribution of the turbulent flow field varying in time and space. Using the numerically modeled instantaneous wake flow fields and AOWT, the dynamic response of a wind turbine, located at specified positions in both tandem and staggered arrangements in a wake, was examined, and the fatigue loads were determined. Furthermore, to determine the major contributions to the fatigue loads, the loads induced by the spatial variation of the mean flow fields were predicted. To the best of the authors' knowledge, no such analysis has been conducted thus far. Importantly, it was found that in the near-wake region, the mean flow field had a significant influence on the fatigue loads, especially in the staggered layout. However, there is no analytical wake model available in the literature capable of predicting the near-wake mean flow fields. Therefore, in this study, a near-wake model was proposed, which yielded satisfactory predictions of the mean velocities in the near-wake region. K E Y W O R D Sblade element method, dynamic response, fatigue load, LES, wake flow, wake model | INTRODUCTIONWind turbines are usually installed as wind farms, in which the upstream wind turbines disturb the upcoming flow field and increase the downstream turbulence. 1-7 Consequently, the fatigue loads on the downstream wind turbines owing to the wake effects are different from those created by a traditional boundary layer flow. 8,9 A method using the effective turbulence intensity 10,11 has been commonly employed to assess the wake effects on the fatigue loads on wind turbines. However, the flow field in a wake is strongly distorted in terms of both the turbulence intensity and the mean flow. As a result, detailed examinations of the wake effects on the fatigue loads are needed. Whereas, the researches 12-15 considering this issue are not as many as those about the fatigue loads induced by the traditional boundary layer. [16][17][18][19][20] This could be owing to the fact that the wind turbine wake flow is much different with the traditional boundary layer flow, failing the applications of the conventional approaches for the turbulent flow generations, 11,21 posing many challenges in determining the fatigue loads on a wind turbine operating in wakes. In recent years, the engineering models, such as

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“…They disclosed that there's a sudden deflection of typhoon direction, which would significantly increase the wind load on the feathering blade. For studies about the aerodynamic performance of wind turbines under different stop positions, Ke et al [20][21][22][23][24] carried out a series of studies based on large eddy simulation (LES) and finite element technology, mainly covering flow field effect, wind pressure distribution, wind-induced response and wind-induced stability under normal wind conditions.…”

Section: Introductionmentioning

confidence: 99%

Aerodynamic Performance and Wind-Induced Responses of Large Wind Turbine Systems with Meso-Scale Typhoon Effects

Wang

2019

Energies

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The theoretical system of existing civil engineering typhoon models is too simplified and the simulation accuracy is very low. Therefore, in this work a meso-scale weather forecast model (WRF) based on the non-static Euler equation model was introduced to simulate typhoon “Nuri” with high spatial and temporal resolution, focusing on the comparison of wind direction and wind intensity characteristics before, during and after the landing of the typhoon. Moreover, the effectiveness of the meso-scale typhoon “Nuri” simulation was verified by a comparison between the track of the typhoon center based on minimum sea level pressure and the measured track. In this paper, the aerodynamic performance of large wind turbines under typhoon loads is studied using WRF and CFD nesting technology. A 5 MW wind turbine located in a wind power plant on the southeast coast of China has been chosen as the research object. The average and fluctuating wind pressure distributions as well as airflow around the tower body and eddy distribution on blade and tower surface were compared. A dynamic and time-historical analysis of wind-induced responses under different stop positions was implemented by considering the finite element complete transient method. The influence of the stop position on the wind-induced responses and wind fluttering factor of the system were analyzed. Finally, under a typhoon process, the most unfavorable stop position of the large wind turbine was concluded. The results demonstrated that the internal force and wind fluttering factor of the tower body increased significantly under the typhoon effect. The wind-induced response of the blade closest to the tower body was affected mostly. The wind fluttering factor of this blade was increased by 35%. It was concluded from the analysis that the large wind turbine was stopped during the typhoon. The most unfavorable stop position was at the complete overlapping of the lower blade and the tower body (Condition 1). The safety redundancy reached the maximum when the upper blade overlapped with the tower body completely (Condition 5). Therefore, it is suggested that during typhoons the blade of the wind turbine be rotated to Condition 5.

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Wind‐induced fatigue of large HAWT coupled tower–blade structures considering aeroelastic and yaw effects

Cited by 17 publications

References 30 publications

Moving Accelerometers to the Tip: Monitoring of Wind Turbine Blade Bending Using 3D Accelerometers and Model-Based Bending Shapes

Moving Accelerometers to the Tip: Monitoring of Wind Turbine Blade Bending Using 3D Accelerometers and Model-Based Bending Shapes

Numerical simulations of fatigue loads on wind turbines operating in wakes

Aerodynamic Performance and Wind-Induced Responses of Large Wind Turbine Systems with Meso-Scale Typhoon Effects

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