CFD study on the impact of yawed inflow on loads, power and near wake of a generic wind turbine

Schulz, Christoph; Letzgus, Patrick; Lutz, Thorsten; Krämer, Ewald

doi:10.1002/we.2004

Cited by 53 publications

(27 citation statements)

References 30 publications

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“…For this purpose a simulation of the power curve on the basis of the stiff straight blade without precone was conducted in steady mode. The comparisons between the different codes of the project partners are presented by Sørensen et al (2015). The FLOWer results showed good agreement with results obtained with EllipSys3D by DTU and MapFLow by NTUA.…”

Section: Code-to-code Validation Of the Simulationssupporting

confidence: 60%

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An investigation of unsteady 3-D effects on trailing edge flaps

et al. 2017

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Abstract. The present study investigates the impact of unsteady 3-D aerodynamic effects on a wind turbine blade with trailing edge flap by means of computational fluid dynamics (CFD). Harmonic oscillations are simulated on the DTU 10 MW rotor with a morphing flap of 10 % chord extent ranging from 70 to 80 % blade radius. The deflection frequency is varied in the range between 1 and 6 p. To quantify 3-D effects, rotor simulations are compared to 2-D airfoil computations and the 2-D theory by Theodorsen. It was found that the deflection of the flap on the 3-D rotor causes a complex wake development and induction which influences the loads over large parts of the blade. In particular, the rotor near wake with its trailing and shed vortex structures revealed a great impact. Trailing vorticity, a 3-D phenomenon, is caused by the gradient of bound circulation along the blade span. Shed vorticity originates from the temporal bound circulation gradient and is thus also apparent in 2-D. Both lead to an amplitude reduction and shed vorticity additionally to a hysteresis of the lift response with regard to the deflection signal in the flap section. A greater amplitude reduction and a less pronounced hysteresis is observed on the 3-D rotor compared to the 2-D airfoil case. Blade sections neighboring the flap experience, however, an opposing impact and hence partly compensate for the negative effect of trailing vortices in the flap section with respect to integral loads. Comparisons to steady flap deflections at the 3-D rotor revealed the high influence of dynamic inflow effects.

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Section: Code-to-code Validation Of the Simulationssupporting

confidence: 60%

“…The process chain for the simulation of wind turbines, which was developed at the Institute of Aerodynamics and Gas Dynamics (IAG), University of Stuttgart (Schulz et al, 2016), is used in the present work. The main part constitutes the CFD code FLOWer of the German Aerospace Center (DLR) (Kroll and Fassbender, 2002).…”

Section: Simulation Process Chainmentioning

confidence: 99%

An investigation of unsteady 3-D effects on trailing edge flaps

et al. 2017

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“…However, there are ongoing research campaigns which seek to understand and quantify the impacts to loading. Already published are studies which consider the impact on loads from operating in yaw using aero-servoelastic wind turbine models (Zalkind and Pao, 2016) and computational fluid dynamics (Schulz et al, 2016). Additionally, there is a currently ongoing field test in which a utility-scale wind turbine which is highly instrumented with load sensors is operated intentionally in yaw to assess impacts (Fleming et al, 2017).…”

Section: Discussionmentioning

confidence: 99%

Field test of wake steering at an offshore wind farm

Fleming

Annoni

Shah³

et al. 2017

Wind Energ. Sci.

261

198

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Abstract. In this paper, a field test of wake-steering control is presented. The field test is the result of a collaboration between the National Renewable Energy Laboratory (NREL) and Envision Energy, a smart energy management company and turbine manufacturer. In the campaign, an array of turbines within an operating commercial offshore wind farm in China have the normal yaw controller modified to implement wake steering according to a yaw control strategy. The strategy was designed using NREL wind farm models, including a computational fluid dynamics model, Simulator fOr Wind Farm Applications (SOWFA), for understanding wake dynamics and an engineering model, FLOw Redirection and Induction in Steady State (FLORIS), for yaw control optimization. Results indicate that, within the certainty afforded by the data, the wake-steering controller was successful in increasing power capture, by amounts similar to those predicted from the models.

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“…This leads to a 1p variation of inflow velocity as seen by the blade. More information about yaw misalignment and its effects can be found in Schulz et al (2017), where the impact of yawed inflow on loads, power and near wake of a generic wind turbine was analyzed.…”

Section: Analysis Of the On-blade Velocitymentioning

confidence: 99%

About the suitability of different numerical methods to reproduce model wind turbine measurements in a wind tunnel with high blockage ratio

Klein¹,

Bartholomay²,

Marten³

et al. 2017

Preprint

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Abstract. Numerical and experimental investigations of a model wind turbine with a diameter of 3.0m are described in the present paper. The objectives of the study are the provision of validation data, the comparison and evaluation of methods of different fidelity and the assessment of the influence of the wind tunnel walls by comparison of measurements to simulations with and without wind tunnel walls. The experiments were carried out in the large wind tunnel of the TU Berlin. With the Lifting Line Free Vortex Wake (LLFVW) code QBlade, the turbine was simulated under far field conditions at the TU Berlin. 5URANS simulations were performed at the University of Stuttgart with the CFD code FLOWer for far field condition to draw a comparison to QBlade. Moreover, CFD simulations of the turbine in a wind tunnel were carried out, as the walls have a significant influence on the turbine performance.Comparisons between experiment, the LLFVW code and CFD include on-blade velocities, angle of attack and bending moments. Comparisons of flow fields are drawn between experiment and the CFD code. 10A good accordance was achieved for the flow fields, the on-blade velocity and the angle of attack, whereas deviations occur for the bending moments.

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CFD study on the impact of yawed inflow on loads, power and near wake of a generic wind turbine

Cited by 53 publications

References 30 publications

An investigation of unsteady 3-D effects on trailing edge flaps

An investigation of unsteady 3-D effects on trailing edge flaps

Field test of wake steering at an offshore wind farm

About the suitability of different numerical methods to reproduce model wind turbine measurements in a wind tunnel with high blockage ratio

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