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Effect of turbulence on the performance of VAWTs: An experimental study in two different wind tunnels

Authors :
Andreu Carbó Molina
Antoine Vergaerde
Gianni Bartoli
Tim De Troyer
Tommaso Massai
Mark Runacres
Engineering Technology
Faculty of Engineering
Industrial Sciences and Technology
Acoustics & Vibration Research Group
Thermodynamics and Fluid Mechanics Group
Source :
Journal of Wind Engineering and Industrial Aerodynamics. 193:103969
Publication Year :
2019
Publisher :
Elsevier BV, 2019.

Abstract

Turbulence is one of the main characteristics of urban flows, but its effect on the performance of small VAWTs (often used in urban wind installations) has not been thoroughly researched. This experimental study focuses in testing a H-Darrieus VAWT prototype in different turbulent conditions inside the wind tunnel, in order to study the influence of turbulence intensity, integral length scales and Reynolds number. Passive grids are used to increase the wind tunnel free stream turbulence up to Iu = 15%, with integral length scales of Lux = 0.18 m and Reynolds numbers of ReD ≈ 300,000. The measurements are repeated in two wind tunnels of different size, which strengthens the results and helps quantify the effect of blockage on the turbine ratings. The results show power coefficient increases up to 20% from smooth (Iu = 0.5%) to turbulent (Iu = 15%) flows, an effect that is enhanced at low λ but that fades as ReD > 400,000. The study of the crossed influence of ReD, Iu and Lux offers valuable data in the process of optimizing the operation of small VAWTs inside urban environments.

Details

ISSN :
01676105
Volume :
193
Database :
OpenAIRE
Journal :
Journal of Wind Engineering and Industrial Aerodynamics
Accession number :
edsair.doi.dedup.....9b501c25ccae2ddc81b7427fe86027d3
Full Text :
https://doi.org/10.1016/j.jweia.2019.103969