Wind turbine wake properties: Comparison between a non-rotating simplified wind turbine model and a rotating model

Aubrun, Sandrine; Loyer, Stéphane; Hancock, P. E.; Hayden, Paul

doi:10.1016/j.jweia.2013.06.007

Cited by 107 publications

(99 citation statements)

References 17 publications

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“…In Section I, examples have been given about stiff structure obtained by modelling the actuator disc with perforated metal plates or by employing a mesh composed by wooden sticks. However, for the present study, the metal-mesh solution adopted by Aubrun et al (2013) and Aubrun et al (2007) was chosen. A 0.6 m diameter porous disc is manufactured by stacking three layers of fine metal mesh with uniform porosity n ¼ 60% and spacing d ¼ 1 mm with two additional larger meshes for structural stiffness (d ¼ 10 mm and d ¼ 50 mm, respectively) as shown in Figure 2.…”

Section: Design Of An Actuator Disc Modelmentioning

confidence: 99%

“…Few studies are available, which analyse the flow field in the near wake of a porous disc with the purpose of emulating a wind turbine wake and examples of various techniques for realising the model can be found. For instance, Aubrun et al (2013) and Aubrun et al (2007) manufactured a small-scale porous disc using fine metal meshes, while perforated metal plates have been adopted by Medici (2005) and Sforza et al (1981). Pierella and Saetran (2010) realised a porous disc with wooden grids.…”

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confidence: 99%

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Experimental comparison of a wind-turbine and of an actuator-disc near wake

Lignarolo

Ragni

Ferreira

et al. 2016

Journal of Renewable and Sustainable Energy

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The actuator disc (AD) model is commonly used to simplify the simulation of horizontal-axis wind-turbine aerodynamics. The limitations of this approach in reproducing the wake losses in wind farm simulations have been proven by a previous research. The present study is aimed at providing an experimental analysis of the near-wake turbulent flow of a wind turbine (WT) and a porous disc, emulating the actuator disc numerical model. The general purpose is to highlight the similarities and to quantify the differences of the two models in the near-wake region, characterised by the largest discrepancies. The velocity fields in the wake of a wind turbine model and a porous disc (emulation of the actuator disc numerical model) have been measured in a wind tunnel using stereo particle image velocimetry. The study has been conducted at low turbulence intensity in order to separate the problems of the flow mixing caused by the external turbulence and the one caused by the turbulence induced directly by the AD or the WT presence. The analysis, as such, showed the intrinsic differences and similarities between the flows in the two wakes, solely due to the wake-induced flow, with no influence of external flow fluctuations. The data analysis provided the time-average three-component velocity and turbulence intensity fields, pressure fields, rotor and disc loading, vorticity fields, stagnation enthalpy distribution, and mean-flow kinetic-energy fluxes in the shear layer at the border of the wake. The properties have been compared in the wakes of the two models. Even in the absence of turbulence, the results show a good match in the thrust and energy coefficient, velocity, pressure, and enthalpy fields between wind turbine and actuator disc. However, the results show a different turbulence intensity and turbulent mixing. The results suggest the possibility to extend the use of the actuator disc model in numerical simulation until the very near wake, provided that the turbulent mixing is correctly represented.

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Section: Design Of An Actuator Disc Modelmentioning

confidence: 99%

mentioning

confidence: 99%

Experimental comparison of a wind-turbine and of an actuator-disc near wake

Lignarolo

Ragni

Ferreira

et al. 2016

Journal of Renewable and Sustainable Energy

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“…An equivalent actuator disk model representing a real turbine in a three-dimensional CFD model offers an economically viable analysis tool, in terms of mesh size and solution timescales, for assessing turbine response in a range of conditions and environments [10]. The properties of the wake behind a three-blade rotating wind turbine and behind a porous disc generating a similar velocity deficit were compared through wind tunnel experiments in [11]. Results have shown that the mean velocity deficit, the stream wise turbulence intensity, the stream-wise skewness and Kurtosis, at the three-diameter of the turbine downstream of a wind turbine and of a porous disc are closely similar in high intensity turbulent inflow conditions.…”

Section: Actuator Disc Modelmentioning

confidence: 99%

Fast Numerical Modelling Method for Wind Flow Investigation Based on Depth-Averaged Equations

Avramenko¹,

Agafonova²,

Sorvari³

et al. 2017

Computational Methods and Experimental Measurements XVIII

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An important phase of wind farm design is solving the wind farm layout optimization problem, which consists in optimally positioning the turbines within the wind farm so that the wake effects are minimized and therefore the expected power production maximized. Simulating a wind farm with more than one fully detailed wind turbine and possibly complex terrain geometry requires significant computational power and time. This paper concerns the study of the depth-averaged flow of the wind turbine with a CFD-RANS approach. The complex three-dimensional (3D) geometry need not be modelled or discretized in the pre-processing state: instead, the geometry of the terrain is only described with source terms in the depth-averaged equations, which are then solved in a very simple and fixed two-dimensional (2D) domain. This approach reduces the equations from 3D to 2D and decreases the elapsed time of CFD simulations from hours to minutes. Thus, it is a very practicable modelling method in real time optimization work. 2D CFD simulations are compared with full 3D models and experiments. This paper gives an overview of the existing work and discusses the challenges that may be overcome by future research.

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“…Nowadays the actuator disc is still used for studying meandering and turbulence decay in turbine wakes, the objective being to maximize the performance of wind Article published by EDP Sciences farms [7]. As for wind turbines, they are investigated by approaches deriving from the lifting line theory.…”

Section: Introductionmentioning

confidence: 99%

“…How this purpose is fulfilled lies beyond the scope of the analysis. Generally the disc consists of a wire netting or a metallic grid [7]. When passing through the disc the viscous stresses developed in the fluid are negligible with regard to the momentum variations issued from sudden changes in direction and enlargements.…”

Section: Introductionmentioning

confidence: 99%

The actuator disc theory for wind turbines including losses and non-uniform velocity distribution

Dyment

2015

Mechanics & Industry

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-In a paper published in 1989 the actuator disc model proposed by Betz to represent the flow across a wind turbine has been set right by taking losses into account. In the present paper this model is improved by introducing global correction factors at the entry and the exit of the machine. The resulting extent of the actuator disc concept shows that management of the velocity field may lead to a satisfactory adjustment between the power output and the velocity deficit range. A significant shift in the characteristics of the machine, associated to a slight enlargement of the wake, is made possible in the frame of the new model. Comparison reveals a better fit with experimental data.

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Wind turbine wake properties: Comparison between a non-rotating simplified wind turbine model and a rotating model

Cited by 107 publications

References 17 publications

Experimental comparison of a wind-turbine and of an actuator-disc near wake

Experimental comparison of a wind-turbine and of an actuator-disc near wake

Fast Numerical Modelling Method for Wind Flow Investigation Based on Depth-Averaged Equations

The actuator disc theory for wind turbines including losses and non-uniform velocity distribution

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