Three-dimensionality of the wake recovery behind a vertical axis turbine

Pablo Ouro, Stefan Runge, Qianyu Luo and Thorsten Stoesser

Renewable Energy, 2019, vol. 133, issue C, 1066-1077

Abstract: The wake recovery downstream of a vertical axis turbine operating in a turbulent channel flow is investigated via detailed velocity measurements using an Acoustic Doppler Velocimeter. Three distinct wake regions are identified: (i) a near-wake region which extends until two rotor diameters (2D) downstream and characterised by a low-momentum area isolated from the ambient flow and the presence of energetic dynamic stall vortices; (ii) a transition region (2D-5D), characterised by a fast momentum recovery, high levels of turbulence and vertical expansion of the wake; and (iii) a far-wake region beyond 5D where the velocity recovers to approximately 95% of the free-stream velocity. Albeit the wake deficit recovery is mostly accomplished at 5D behind the turbine, rotor-induced effects are still present beyond 10D as indicated by high-order flow statistics, such as high velocity fluctuations and flow skewness. The analysis of the streamwise momentum budget reveals that advection is the main mechanism for momentum replenishment through most of the wake and turbulent transport terms play only a minor role. This study evidences the anisotropic nature of the turbulence and asymmetry of the flow in horizontal, vertical and cross-sectional planes downstream of the vertical axis turbine.

Keywords: Vertical axis turbine; Wake recovery; Array; Acoustic Doppler velocimeter; Turbulence; Renewable energy (search for similar items in EconPapers)
Date: 2019
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (18)

Downloads: (external link)
http://www.sciencedirect.com/science/article/pii/S096014811831317X
Full text for ScienceDirect subscribers only

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:eee:renene:v:133:y:2019:i:c:p:1066-1077

DOI: 10.1016/j.renene.2018.10.111

Access Statistics for this article

Renewable Energy is currently edited by Soteris A. Kalogirou and Paul Christodoulides

More articles in Renewable Energy from Elsevier
Bibliographic data for series maintained by Catherine Liu ().