Characterisation of a horizontal axis wind turbine’s tip and root vortices

Sherry, M.; Sheridan, John; Jacono, David Lo

doi:10.1007/s00348-012-1417-y

Cited by 66 publications

(63 citation statements)

References 38 publications

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“…Sci., 1, 89-100, 2016 www.wind-energ-sci.net/1/89/2016/ The fact that γ chordwise is distributed over such a large area of the root might explain that the root vortex does not present a well-defined, distinctive structure, as Vermeer et al (2003), Massouh and Dobrev (2007), and Haans et al (2008) reported in their experimental wake studies of different wind turbines. Furthermore, the existence of two adjacent root regions with counter-rotating γ chordwise might also explain the fast diffusion of the root vortex reported by Ebert and Wood (2001) and Sherry et al (2013).…”

Section: The Origin Of the Root Vortexmentioning

confidence: 89%

“…For instance, Massouh and Dobrev (2007) and Haans et al (2008) also came to that conclusion after studying a wind turbine rotor wake with particle image velocimetry (PIV) and hot film wake measurements, respectively. Furthermore, Ebert and Wood (2001) and Sherry et al (2013) observed by means of PIV (among other measurement techniques) that the root vortex diffuses very rapidly. The PIV measurements performed by Akay et al (2012) on two different rotors demonstrated that the evolution and strength of the root vortex highly depends on the blade root geometry and the spanwise distribution of circulation.…”

Section: The Root Vortexmentioning

confidence: 98%

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Detailed analysis of the blade root flow of a horizontal axis wind turbine

et al. 2016

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Abstract. The root flow of wind turbine blades is subjected to complex physical mechanisms that influence significantly the rotor aerodynamic performance. Spanwise flows, the Himmelskamp effect, and the formation of the root vortex are examples of interrelated aerodynamic phenomena that take place in the blade root region. In this study we address those phenomena by means of particle image velocimetry (PIV) measurements and Reynolds-averaged Navier-Stokes (RANS) simulations. The numerical results obtained in this study are in very good agreement with the experiments and unveil the details of the intricate root flow. The Himmelskamp effect is shown to delay the stall onset and to enhance the lift force coefficient C l even at moderate angles of attack. This improvement in the aerodynamic performance occurs in spite of the negative influence of the mentioned effect on the suction peak of the involved blade sections. The results also show that the vortex emanating from the spanwise position of maximum chord length rotates in the opposite direction to the root vortex, which affects the wake evolution. Furthermore, the aerodynamic losses in the root region are demonstrated to take place much more gradually than at the tip.

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Section: The Origin Of the Root Vortexmentioning

confidence: 89%

Section: The Root Vortexmentioning

confidence: 98%

Detailed analysis of the blade root flow of a horizontal axis wind turbine

et al. 2016

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“…A comparison between a WT wake and an AD wake in the presence of leapfrogging is for this reason of particular interest. Following the experimental studies of Dobrev et al (2008), Felli et al (2011), andSherry et al (2010), Lignarolo et al (2014a) have shown how the instability of the tip-vortex helix has a major effect on the wake mixing and re-energising mechanism. Lignarolo et al (2015a) have conducted a detailed analysis of the effect on the turbulence field and wake mixing due to the presence of the leapfrogging instability.…”

mentioning

confidence: 89%

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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“…Smoke visualizations of tip vortices are shown in Figure 11. The root vortices are more difficult to track in experiments and have been only observed much closer to the rotor plane, as, for example, in the recent PIV measurements undertaken [39,44]. It is most probable that the root vortex diffuses rapidly due to the interference effects of the turbine support structure.…”

Section: Wake Characteristicsmentioning

confidence: 95%

“…Such measurements have been performed by [50] and in the MEXICO experiment (see [51]). More recent PIV measurements include those undertaken at TUDelft [39,52], at NTNU [53] and at Monash University (see [44]). In the experiment by [50], PIV measurements were obtained at various blade azimuthal positions.…”

Section: Wake Characteristicsmentioning

confidence: 99%

A Review of Wind Turbine Yaw Aerodynamics

Micallef¹,

Sant²

2016

Wind Turbines - Design, Control and Applications

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The fundamental physics of HAWT aerodynamics in yaw is reviewed with reference to some of the latest scientific research covering both measurements and numerical modelling. The purpose of this chapter is to enable a concise overview of this important subject in rotor aerodynamics. This will provide the student, researcher or industry professional a quick reference. Detailed references are included for those who need to delve deeper into the subject. The chapter is also restricted to the aerodynamics of single rotors and their wake characteristics. Far wake and wind turbine to turbine effects experienced in wind farms are excluded from this review. Finally, a future outlook is provided in order to inspire further research in yawed aerodynamics.

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Characterisation of a horizontal axis wind turbine’s tip and root vortices

Cited by 66 publications

References 38 publications

Detailed analysis of the blade root flow of a horizontal axis wind turbine

Detailed analysis of the blade root flow of a horizontal axis wind turbine

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

A Review of Wind Turbine Yaw Aerodynamics

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