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Efficiency improvement of vertical axis wind turbines with an upstream deflector.

Stout, Craig; Islam, Sheikh; White, Alasdair; Arnott, Scott; Kollovozi, Erald; Shaw, Morven; Droubi, Ghazi; Sinha, Yashwant; Bird, Benjamin


Craig Stout

Alasdair White

Scott Arnott

Erald Kollovozi

Morven Shaw

Yashwant Sinha

Benjamin Bird


The suitability of using an upstream deflector to improve the efficiency of a vertical axis wind turbine is presented in this study. A two-dimensional vertical axis wind turbine (VAWT) was modelled and simulated using ANSYS Fluent 14.0 computational fluid dynamics (CFD) software to solve the k-epsilon (RNG) turbulence model. Firstly, the open rotor design was optimised by varying orientation and pitch angle, prior to analysing the effect increasing wind speed had on the turbine performance. A maximum efficiency of 19.101% was achieved and was used as the open rotor design. A series of curved upstream deflectors were then evaluated in terms of efficiency improvements against the original open rotor design. Installation of the deflector resulted in a redirection of the fluid flow from the returning turbine blade, therefore reducing the negative torque induced on the system. Additionally, deflector width angles of 45o and 36o were found to improve the turbine performance by 1.266%. Finally, a scale model of the wind turbine was constructed and experimentally tested using a wind tunnel. No correlation between the CFD and experimental results was found due to variations in the wind speed tested by both methods. However, the VAWT design operated at a reasonably efficient level during the experimental testing, even under suboptimal conditions.


STOUT, C., ISLAM, S., WHITE, A., ARNOTT, S., KOLLOVOZI, E., SHAW, M., DROUBI, G., SINHA, Y. and BIRD, B. 2017. Efficiency improvement of vertical axis wind turbines with an upstream deflector. Energy procedia [online], 118: proceedings of the 2nd International conference on advances on clean energy research (ICACER 2017), 7-9 April 2017, Berlin, Germany, pages 141-148. Available from:

Journal Article Type Conference Paper
Conference Name 2nd International conference on advances on clean energy research (ICACER 2017)
Conference Location Berlin, Germany
Start Date Apr 7, 2017
End Date Apr 9, 2017
Acceptance Date Jan 15, 2017
Online Publication Date Sep 11, 2017
Publication Date Aug 31, 2017
Deposit Date Sep 14, 2017
Publicly Available Date Sep 14, 2017
Journal Energy Procedia
Print ISSN 1876-6102
Electronic ISSN 1876-6102
Publisher Elsevier
Peer Reviewed Peer Reviewed
Volume 118
Pages 141-148
Series ISSN 1876-6102
Keywords Vertical axis wind turbine (VAWT); Upstream deflector; CFD; Wind tunnel
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