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Transition to bluff-body dynamics in the wake of vertical-axis wind turbines

  • Daniel B. Araya (a1), Tim Colonius (a2) and John O. Dabiri (a3)
Abstract

We present experimental data to demonstrate that the far wake of a vertical-axis wind turbine (VAWT) exhibits features that are quantitatively similar to that of a circular cylinder with the same aspect ratio. For a fixed Reynolds number ( $Re\approx 0.8\times 10^{5}$ ) and variable tip-speed ratio, two-dimensional particle image velocimetry (PIV) is used to measure the velocity field in the wake of four different laboratory-scale models: a 2-bladed, 3-bladed and 5-bladed VAWT, as well as a circular cylinder. With these measurements, we use spectral analysis and proper orthogonal decomposition (POD) to evaluate statistics of the velocity field and investigate the large-scale coherent motions of the wake. In all cases, we observe three distinct regions in the VAWT wake: (i) the near wake, where periodic blade vortex shedding dominates; (ii) a transition region, where growth of a shear-layer instability occurs; (iii) the far wake, where bluff-body wake oscillations dominate. We define a dynamic solidity parameter, $\unicode[STIX]{x1D70E}_{D}$ , that relates the characteristic scales of the flow to the streamwise transition location in the wake. In general, we find that increasing $\unicode[STIX]{x1D70E}_{D}$ leads to an earlier transition, a greater initial velocity deficit and a faster rate of recovery in the wake. We propose a coordinate transformation using $\unicode[STIX]{x1D70E}_{D}$ in which the minimum velocity recovery profiles of the VAWT wake closely match that of the cylinder wake. The results have implications for manipulating VAWT wake recovery within a wind farm.

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Email address for correspondence: dbaraya@uh.edu
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S. J. Andersen , J. N. Sørensen  & R. Mikkelsen 2013 Simulation of the inherent turbulence and wake interaction inside an infinitely long row of wind turbines. J. Turbul. 14, 124.

D. B. Araya  & J. O. Dabiri 2015 A comparison of wake measurements in motor-driven and flow-driven turbine experiments. Exp. Fluids 56 (7), 115.

P. Bachant  & M. Wosnik 2015 Characterising the near-wake of a cross-flow turbine. J. Turbul. 16 (4), 392410.

G. Berkooz , P. Holmes  & J. L. Lumley 1993 The proper orthogonal decomposition in the analysis of turbulent flows. Annu. Rev. Fluid Mech. 25, 539575.

M. Calaf , C. Meneveau  & J. Meyers 2010 Large eddy simulation study of fully developed wind-turbine array boundary layers. Phys. Fluids 22, 015110.

L. P. Chamorro , C. Hill , S. Morton , C. Ellis , R. E. A. Arndt  & F. Sotiropoulos 2013 On the interaction between a turbulent open channel flow and an axial-flow turbine. J. Fluid Mech. 716, 658670.

J. O. Dabiri 2014 Emergent aerodynamics in wind farms. Phys. Today 67, 6667.

R. Dunne  & B. J. McKeon 2015 Dynamic stall on a pitching and surging airfoil. Exp. Fluids 56 (8), 115.

J. M. Edwards , L. A. Danao  & R. J. Howell 2015 PIV measurements and CFD simulation of the performance and flow physics and of a small-scale vertical axis wind turbine. Wind Energy 18, 201217.

L.-H. Feng , J.-J. Wang  & C. Pan 2011 Proper orthogonal decomposition analysis of vortex dynamics of a circular cylinder under synthetic jet control. Phys. Fluids 23, 014106.

C. S. Ferreira , G. van Kuik , G. van Bussel  & F. Scarano 2009 Visualization by PIV of dynamic stall on a vertical axis wind turbine. Exp. Fluids 46, 97108.

N. Fujisawa  & S. Shibuya 2001 Observations of dynamic stall on Darrieus wind turbine blades. J. Wind Engng Ind. Aerodyn. 89, 201214.

N. Hamilton , M. Tutkun  & R. B. Cal 2015 Wind turbine boundary layer arrays for Cartesian and staggered configurations: part II, low-dimensional representations via the proper orthogonal decomposition. Wind Energy 18, 297315.

M. O. L. Hansen , J. N. Sørensen , S. Voutsinas , N. Sørensen  & H. A. Madsen 2006 State of the art in wind turbine aerodynamics and aeroelasticity. Prog. Aerosp. Sci. 42, 285330.

U. D. Högström , D. N. Asimakopoulos , H. Kambezidis , C. G. Helmist  & A. Smedman 1988 A field study of the wake behind a 2MW wind turbine. Atmos. Environ. 22, 803820.

G. V. Iungo  & Fernando Porté-Agel 2014 Volumetric lidar scanning of wind turbine wakes under convective and neutral atmospheric stability regimes. J. Atmos. Ocean. Technol. 31, 20352048.

G. V. Iungo , F. Viola , S. Camarri , F. Porté-Agel  & F. Gallaire 2013 Linear stability analysis of wind turbine wakes performed on wind tunnel measurements. J. Fluid Mech. 737, 499526.

M. Kinzel , Q. Mulligan  & J. O. Dabiri 2012 Energy exchange in an array of vertical-axis wind turbines. J. Turbul. 13 (38), 113.

J. Kostas , J. Soria  & M. S. Chong 2005 A comparison between snapshot POD analysis of PIV velocity and vorticity data. Exp. Fluids 38, 146160.

K. M. Lam 2009 Vortex shedding flow behind a slowly rotating circular cylinder. J. Fluids Struct. 25, 245262.

A. Laneville  & P. Vittecoq 1986 Dynamic stall: the case of the vertical axis wind turbine. J. Solar Energy Engng 108, 140145.

G. C. Larsen , H. A. Madsen , K. Thomsen  & T. J. Larsen 2008 Wake meandering: a pragmatic approach. Wind Energy 11, 377395.

D. Medici  & P. H. Alfredsson 2006 Measurements on a wind turbine wake: 3D effects and bluff body vortex shedding. Wind Energy 9, 219236.

D. Medici  & P. H. Alfredsson 2008 Measurements behind model wind turbines: further evidence of wake meandering. Wind Energy 11, 211217.

S. Mittal  & B. Kumar 2003 Flow past a rotating cylinder. J. Fluid Mech. 476, 303334.

L. E. Myers  & A. S. Bahaj 2010 Experimental analysis of the flow field around horizontal axis tidal turbines by use of scale mesh disk rotor simulators. Ocean Engng 37, 218227.

V. L. Okulov , I. V. Naumov , R. F. Mikkelsen , I. K. Kabardin  & J. N. Sørensen 2014 A regular strouhal number for large-scale instability in the far wake of a rotor. J. Fluid Mech. 747, 369380.

C. Picard  & J. Delville 2000 Pressure velocity coupling in a subsonic round jet. Intl J. Heat Fluid Flow 21, 359364.

A. Roshko 1961 Experiments on the flow past a circular cylinder at very high Reynolds number. J. Fluid Mech. 10, 345356.

G. Tescione , D. Ragni , C. He , C. J. Ferreira ,  & G. J. W. van Bussel 2014 Near wake flow analysis of a vertical axis wind turbine by stereoscopic particle image velocimetry. J. Renew. Energ. 70, 4761.

K. Thomsen  & P. Sørensen 1999 Fatigue loads for wind turbines operating in wakes. J. Wind Engng Ind. Aerodyn. 80, 121136.

C. VerHulst  & C. Meneveau 2014 Large eddy simulation study of the kinetic energy entrainment by energetic turbulent flow structures in large wind farms. Phys. Fluids 26, 025113.

L. J. Vermeer , J. N. Sørensen  & A. Crespo 2003 Wind turbine wake aerodynamics. Prog. Aerosp. Sci. 39, 467510.

P. D. Welch 1967 The use of fast Fourier transform for the estimation of power spectra: a method based on time averaging over short, modified periodograms. IEEE Trans. Audio Electroacoust. 15, 7073.

W. Zhang , C. D. Markfort  & F. Porté-Agel 2013 Wind turbine wakes in a convective boundary layer: a wind tunnel-study. Boundary-Layer Meteorol. 146, 161179.

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Journal of Fluid Mechanics
  • ISSN: 0022-1120
  • EISSN: 1469-7645
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