Elastic actuator line modelling for wake-induced fatigue analysis of horizontal axis wind turbine blade

Meng, Hang; Lien, Fue‐Sang; Li, Li

doi:10.1016/j.renene.2017.08.074

Cited by 66 publications

(33 citation statements)

References 26 publications

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“…Moreover, ALM is also an effective technique for predicting the loading on the blades with only simple structured grids, which has been proved by Troldborg [12]. Recently, Meng et al [13] firstly proposed the concept of the elastic actuator line (EAL), which combines ALM and a finite difference structural model. In the EAL model, the elastic blades are incorporated into ALM and its simulation results are closer to the reality.…”

Section: Introductionmentioning

confidence: 99%

Study on Actuator Line Modeling of Two NREL 5-MW Wind Turbine Wakes

Zheng

2018

Applied Sciences

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Abstract:The wind turbine wakes impact the efficiency and lifespan of the wind farm. Therefore, to improve the wind plant performance, research on wind plant control is essential. The actuator line model (ALM) is proposed to simulate the wind turbine efficiently. This research investigates the National Renewable Energy Laboratory 5 Million Watts (NREL 5-MW) wind turbine wakes with Open Field Operation and Manipulation (OpenFOAM) using ALM. Firstly, a single NREL 5-MW turbine is simulated. The comparison of the power and thrust with Fatigue, Aerodynamics, Structures, and Turbulence (FAST) shows a good agreement below the rated wind speed. The information relating to wind turbine wakes is given in detail. The top working status is proved at the wind speed of 8 m/s and the downstream distance of more than 5 rotor diameters (5D). Secondly, another case with two NREL 5-MW wind turbines aligned is also carried out, in which 7D is validated as the optimum distance between the two turbines. The result also shows that the upstream wind turbine has an obvious influence on the downstream one.

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Section: Introductionmentioning

confidence: 99%

Study on Actuator Line Modeling of Two NREL 5-MW Wind Turbine Wakes

Zheng

2018

Applied Sciences

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“…It is important in the blade design process to include fatigue damage constraints because the design life for wind turbines is often 20 or more years. Many wind turbine component designs, including the blade, are driven by constraints on the fatigue damage …”

Section: Introductionmentioning

confidence: 99%

“…Many wind turbine component designs, including the blade, are driven by constraints on the fatigue damage. [4][5][6][7] The fatigue damage is determined from the dynamic loading experienced by the wind turbine. Calculating the dynamic loading requires performing an unsteady simulation and is thus computationally expensive compared with the rest of the design analysis.…”

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confidence: 99%

Efficient incorporation of fatigue damage constraints in wind turbine blade optimization

Ingersoll

Ning

2020

Wind Energy

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Wind turbine design is a challenging multidisciplinary optimization problem, where the aerodynamic shapes, structural member sizing, and material composition must all be determined and optimized. Some previous blade design methods incorporate static loading with an added safety factor to account for dynamic effects. Others incorporate dynamic loading, but in general limit, the evaluation to a few design cases. By not fully incorporating the dynamic loading of the wind turbine, the final turbine blade design is either too conservative by overemphasizing the dynamic effects or infeasible by failing to adequately account for these effects. We propose an iterative method that estimates fatigue effects during the optimization process while quickly converging to the true solution. We also demonstrate an alternate approach where a surrogate model is trained to efficiently estimate the dynamic loading of the wind turbine in the design process. This surrogate model, once trained, was then incorporated in the optimization loop of the wind turbine blade. In contrast to the iterative method, there is significant upfront computational cost to construct the surrogate model. However, this surrogate model has been generalized to be used for different rated turbines and can predict the fatigue damage of a wind turbine with less than 5% error for baseline wind turbines of the same family. These methods can be used instead of the more computationally expensive method of calculating the dynamic loading of the turbine within the optimization routine.

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“…As a result, detailed examinations of the wake effects on the fatigue loads are needed. Whereas, the researches considering this issue are not as many as those about the fatigue loads induced by the traditional boundary layer . 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, posing many challenges in determining the fatigue loads on a wind turbine operating in wakes.…”

Section: Introductionmentioning

confidence: 99%

“…However, the time histories of the wake flow fields acting on the downstream wind turbines were generated using the traditional analytical method, and hence were different from the real wake flows. Recently, Meng et al developed an elastic actuator line model (ALM) to simulate the dynamic responses of wind turbines in the wake. Two staggered turbines in a neutral atmospheric condition were examined and it was found that the downstream wind turbine suffered higher fatigue loads than the upstream one.…”

Section: Introductionmentioning

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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Elastic actuator line modelling for wake-induced fatigue analysis of horizontal axis wind turbine blade

Cited by 66 publications

References 26 publications

Study on Actuator Line Modeling of Two NREL 5-MW Wind Turbine Wakes

Study on Actuator Line Modeling of Two NREL 5-MW Wind Turbine Wakes

Efficient incorporation of fatigue damage constraints in wind turbine blade optimization

Numerical simulations of fatigue loads on wind turbines operating in wakes

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