The near wake of a model horizontal-axis wind turbine—I. Experimental arrangements and initial results

Ebert, P.; Wood, David

doi:10.1016/s0960-1481(97)00046-3

Cited by 61 publications

(29 citation statements)

References 13 publications

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“…Whereas the traditional approach predicts 〈V q 〉 to be positive everywhere, the new data reduction predicts sign changes. Qualitative comparison with near-wake velocity studies by Ebert and Wood 6 and Vermeer 14 confi rms the 〈V q 〉 shape. The new data reduction technique yields more detail in the 〈V r 〉 and 〈V q 〉-distribution than the traditional technique.…”

Section: Trends In Azimuth Angle-dependent Velocitysupporting

confidence: 56%

HAWT near‐wake aerodynamics, Part I: axial flow conditions

et al. 2008

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An improved physical understanding of the rotor aerodynamics of a horizontal axis wind turbine (HAWT) is required to reduce the uncertainties associated with today's design codes. Wind tunnel experiments contribute to increased knowledge and enable validation and construction of models. The present study focuses on the near-wake of a model HAWT in both axial and yawed flow conditions. At three downstream planes parallel to the rotor plane, single-sensor hot-film traverses are made. The phase-locked unsteady threedimensional flow velocity vector is determined by a novel data reduction method. A series of two papers discusses the near-wake aerodynamics of a model HAWT. The main goals are to obtain a detailed understanding of the near-wake development and to arrive at a base for model construction and validation. The first paper presents the experimental setup, data reduction and the results for the baseline case (axial flow conditions).In the second paper, the results for the yawed flow cases are presented and the effect of yaw misalignment on the near-wake development is discussed.

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Section: Trends In Azimuth Angle-dependent Velocitysupporting

confidence: 56%

HAWT near‐wake aerodynamics, Part I: axial flow conditions

et al. 2008

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“…In order to study the streamlines and obtain the detailed information of flow around the wind turbine, a flow visualization and velocity measurement are important. Investigation [5] has been carried out for this sake. Considerable improvements in the understanding of contrarotating wind turbine system can be achieved through proper instrumentation and experimental measurements.…”

Section: Contrarotating Blade Systemmentioning

confidence: 99%

Performance of a Contrarotating Small Wind Energy Converter

Habash

Groza

Yang

et al. 2011

ISRN Mechanical Engineering

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Responding to more demand in coming years, the task of the small wind energy industry requires progress on several fronts-the public policy initiatives, technology development, and market growth. One important issue of the wind energy utilization is the conversion efficiency of the usable energy into productive power. Enhanced technologies such as contrarotating blades, gearbox and lubrication, airfoils, generators, and power electronics will lower cost and increase energy production. The purpose of this paper is, therefore, to reinforce the effectiveness of employing contrarotating system to enhance the performance of a small wind energy converter (SWEC). With this concept, the SWEC works more efficiently and therefore produces more energy in a unit turbine area. To verify the SWEC performance, a research model has been built and tested over a range of operating conditions. Wind tunnel tests were carried out to ascertain the overall performance of the contrarotating SWEC. Results are presented for cases of different wind speeds and Reynolds number. The results demonstrated a significant increase in wind energy conversion efficiency and capability of operation at lower wind speeds while keeping up performance compared to a single-rotor system of the same type.

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“…7,8 Also, the wake structure of a single wind turbine is a fairly well explored topic, [9][10][11][12][13][14][15][16][17][18] together with superposition effects of a finite number of wakes and their mutual interactions. [19][20][21][22][23][24][25] Pioneering works of Lissaman 26 and later Frandsen 25 led the way for understanding and modeling of an "infinite," or fully developed, array of wind turbines.…”

Section: Introductionmentioning

confidence: 99%

Large eddy simulation study of scalar transport in fully developed wind-turbine array boundary layers

2011

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Mechanical stability of ordered droplet packings in microfluidic channels Appl. Phys. Lett. 99, 244104 (2011) Numerical investigation and evaluation of optimum hydrodynamic performance of a horizontal axis hydrokinetic turbine J. Wind harvesting is fast becoming an important alternative source of energy. As wind farms become larger, they begin to attain scales at which two-way interactions with the atmospheric boundary layer (ABL) must be taken into account. Several studies have shown that there is a quantifiable effect of wind farms on the local meteorology, mainly through changes in the land-atmosphere fluxes of heat and moisture. In particular, the observed trends suggest that wind farms increase fluxes at the surface and this could be due to increased turbulence in the wakes. Conversely, simulations and laboratory experiments show that underneath wind farms, the friction velocity is decreased due to extraction of momentum by the wind turbines, a factor that could decrease scalar fluxes at the surface. In order to study this issue in more detail, a suite of large eddy simulations of an infinite (fully developed) wind turbine array boundary layer, including scalar transport from the ground surface without stratification, is performed. Results show an overall increase in the scalar fluxes of about 10%-15% when wind turbines are present in the ABL, and that the increase does not strongly depend upon wind farm loading as described by the turbines' thrust coefficient and the wind turbines spacings. A single-column analysis including scalar transport shows that the presence of wind farms can be expected to increase slightly the scalar transport from the bottom surface and that this slight increase is due to a delicate balance between two strong opposing trends.

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The near wake of a model horizontal-axis wind turbine—I. Experimental arrangements and initial results

Cited by 61 publications

References 13 publications

HAWT near‐wake aerodynamics, Part I: axial flow conditions

HAWT near‐wake aerodynamics, Part I: axial flow conditions

Performance of a Contrarotating Small Wind Energy Converter

Large eddy simulation study of scalar transport in fully developed wind-turbine array boundary layers

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