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Aerodynamics of Vertical-Axis Wind Turbines in Full-Scale and Laboratory-Scale Experiments


Araya, Daniel Borsodi (2016) Aerodynamics of Vertical-Axis Wind Turbines in Full-Scale and Laboratory-Scale Experiments. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/Z9VD6WC2 .


Within a wind farm, multiple turbine wakes can interact and have a substantial effect on the overall power production. This makes an understanding of the wake recovery process critically important to optimizing wind farm efficiency. Vertical-axis wind turbines (VAWTs) exhibit features that are amenable to dramatically improving this efficiency. However, the physics of the flow around VAWTs is not well understood, especially as it pertains to wake interactions, and it is the goal of this thesis to partially fill this void. This objective is approached from two broadly different perspectives: a low-order view of wind farm aerodynamics, and a detailed experimental analysis of the VAWT wake.

One of the contributions of this thesis is the development of a semi-empirical model of wind farm aerodynamics, known as the LRB model, that is able to predict turbine array configurations to leading order accuracy. Another contribution is the characterization of the VAWT wake as a function of turbine solidity. It was found that three distinct regions of flow exist in the VAWT wake: (1) the near wake, where periodic blade shedding of vorticity dominates; (2) a transition region, where growth of a shear-layer instability occurs; (3) the far wake, where bluff-body oscillations dominate. The wake transition can be predicted using a new parameter, the dynamic solidity, which establishes a quantitative connection between the wake of a VAWT and that of a circular cylinder. The results provide insight into the mechanism of the VAWT wake recovery and the potential means to control it.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:VAWT, vertical-axis wind turbine, wind turbine aerodynamics, wind energy, wake flow, bluff body wake dynamics
Degree Grantor:California Institute of Technology
Division:Engineering and Applied Science
Major Option:Aeronautics
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Dabiri, John O.
Group:Resnick Sustainability Institute, GALCIT
Thesis Committee:
  • McKeon, Beverley J. (chair)
  • Colonius, Tim
  • Leonard, Anthony
  • Dabiri, John O.
Defense Date:13 November 2015
Funding AgencyGrant Number
National Science Foundation Graduate Research FellowshipUNSPECIFIED
U.S. Department of Defense National Defense Science and Engineering Graduate FellowshipUNSPECIFIED
Resnick Sustainability Institute Graduate Research FellowshipUNSPECIFIED
Office of Naval ResearchN000141211047
Gordon and Betty Moore FoundationGBMF2645
Record Number:CaltechTHESIS:12022015-023535926
Persistent URL:
Related URLs:
URLURL TypeDescription adapted for ch. 2
http://dx/ adapted for ch. 3
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:9303
Deposited By: Daniel Araya
Deposited On:08 Dec 2015 17:28
Last Modified:25 Oct 2023 21:05

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