Linear stability analysis of wind turbine wakes performed on wind tunnel measurements

Iungo, Giacomo Valerio; Viola, Francesco; Camarri, Simone; Porté‐Agel, Fernando; Gallaire, François

doi:10.1017/jfm.2013.569

Cited by 114 publications

(125 citation statements)

References 44 publications

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“…In the light of the above-mentioned benefits of wind tunnel experiments, they have been widely used in the wind-energy community to study wind turbines and their wakes (e.g., [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21]). However, …”

Section: Introductionmentioning

confidence: 99%

A New Miniature Wind Turbine for Wind Tunnel Experiments. Part I: Design and Performance

Bastankhah

Porté‐Agel

2017

Energies

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Miniature wind turbines, employed in wind tunnel experiments to study the interaction of turbines with turbulent boundary layers, usually suffer from poor performance with respect to their large-scale counterparts in the field. Moreover, although wakes of wind turbines have been extensively examined in wind tunnel studies, the proper characterization of the performance of wind turbines has received relatively less attention. In this regard, the present study concerns the design and the performance analysis of a new three-bladed horizontal-axis miniature wind turbine with a rotor diameter of 15 cm. Due to its small size, this turbine, called WiRE-01, is particularly suitable for studies of wind farm flows and the interaction of the turbine with an incoming boundary-layer flow. Especial emphasis was placed on the accurate measurement of the mechanical power extracted by the miniature turbine from the incoming wind. In order to do so, a new setup was developed to directly measure the torque of the rotor shaft. Moreover, to provide a better understanding on the connection between the mechanical and electrical aspects of miniature wind turbines, the performance of three different direct-current (DC) generators was studied. It is found that electrical outputs of the tested generators can be used to provide a rather acceptable estimation of the mechanical input power. Force and power measurements showed that the thrust and power coefficients of the miniature turbine can reach 0.8 and 0.4, respectively, which are close to the ones of large-scale turbines in the field. In Part II of this study, the wake structure and dynamic flow characteristics are studied for the new miniature turbine immersed in a turbulent boundary-layer flow.

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Section: Introductionmentioning

confidence: 99%

A New Miniature Wind Turbine for Wind Tunnel Experiments. Part I: Design and Performance

Bastankhah

Porté‐Agel

2017

Energies

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“…Thus, an extensive understanding of the wake characteristics is preferable and many studies have been carried out in this field, see [8] and [9] for instance. The complex dynamics of vortical structures accounting for the development of wind turbine wakes have been addressed in [10] and [11]. However in AWE, the interaction between airborne systems and their environment…”

Section: Introductionmentioning

confidence: 99%

Comparison study between wind turbine and power kite wakes

Haas

Meyers

2017

J. Phys.: Conf. Ser.

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“…However, the interaction of turbine wakes with boundary-layer flows has gradually received more attention in the wind energy community as wind turbines operate in the atmospheric boundary-layer (ABL) flow. In particular, during the last ten years, wind tunnel experiments (e.g., [8][9][10][11][12][13][14][15][16][17][18][19]) have been performed to study wakes of down-scaled wind turbines in boundary-layer flows. These works sought to provide a better understanding on turbine wake characteristics.…”

Section: Introductionmentioning

confidence: 99%

A New Miniature Wind Turbine for Wind Tunnel Experiments. Part II: Wake Structure and Flow Dynamics

Bastankhah

Porté‐Agel

2017

Energies

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An optimized three-bladed horizontal-axis miniature wind turbine, called WiRE-01, with the rotor diameter of 15 cm is designed and fully characterized in Part I of this study. In the current part of the study, we investigate the interaction of the turbine with a turbulent boundary layer. The comparison of the spectral density of the thrust force and the one of the incoming velocity revealed new insights on the use of turbine characteristics to estimate incoming flow conditions. High-resolution stereoscopic particle image-velocimetry (S-PIV) measurements were also performed in the wake of the turbine operating at optimal conditions. Detailed information on the velocity and turbulence structure of the turbine wake is presented and discussed, which can serve as a complete dataset for the validation of numerical models. The PIV data are also used to better understand the underlying mechanisms leading to unsteady loads on a downstream turbine at different streamwise and spanwise positions. To achieve this goal, a new method is developed to quantify and compare the effect of both turbulence and mean shear on the moment of the incoming momentum flux for a hypothetical turbine placed downstream. The results show that moment fluctuations caused by turbulence are bigger under full-wake conditions, whereas those caused by mean shear are clearly dominant under partial-wake conditions. Especial emphasis is also placed on how the mean wake flow distribution is affected by wake meandering. Conditional averaging based on the instantaneous position of the wake center revealed that when the wake meanders laterally to one side, a high-speed region exists on the opposite side. The results show that, due to this high-speed region, large lateral meandering motions do not lead to the expansion of the mean wake cross-section in the lateral direction.

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Linear stability analysis of wind turbine wakes performed on wind tunnel measurements

Cited by 114 publications

References 44 publications

A New Miniature Wind Turbine for Wind Tunnel Experiments. Part I: Design and Performance

A New Miniature Wind Turbine for Wind Tunnel Experiments. Part I: Design and Performance

Comparison study between wind turbine and power kite wakes

A New Miniature Wind Turbine for Wind Tunnel Experiments. Part II: Wake Structure and Flow Dynamics

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