Large Eddy Simulation of flow around a single and two in-line horizontal-axis wind turbines

• Published in: Energy (Oxford) 2017-02, Vol.121 (C), p.533-544
• Main Authors: Amin Allah, Veisi, Shafiei Mayam, Mohammad Hossein
• Format: Article
• Language: English
• Subjects: Computational fluid dynamics; Downstream; Downstream effects; Energy efficiency; Horizontal Axis Wind Turbines; Large Eddy Simulation; Residual stress; Smagorinsky model; Studies; Turbines; Turbulence; Turbulence intensity; Velocity; Vortices; Wind power; Wind turbine; Wind turbines
• ISSN: 0360-5442; 1873-6785
• DOI: 10.1016/j.energy.2017.01.052

A Large Eddy Simulation (LES) has been employed in order to study the flow field in a single-wind turbine and in two in-line wind turbines. The present study focuses on the flow around a horizontal axis wind turbine in a virtual wind tunnel. The anisotropic residual stress tensor is driven by the Smagorinsky model. The results are consistent with experimental data presented in literature. Streamwise velocity is increased and cross stream velocity is decreased as wake moves in downstream direction. A faster rate of wake recovery is seen for the two in-line setup. The results reveal that turbulence intensity is increased by increasing the downstream distance and two in-line turbines show greater intensity. Wind turbine performance can be affected by the turbulent structures. If this phenomenon occurs, information about turbulent structures would be useful in order to investigate the effect of turbulent structures on wind turbine performance. As a result, we aim to reveal the effect of turbulent structures, by using the λci technique in this study, and to investigate the performance of wind turbines in different conditions. Furthermore, the effects of blade rotation direction are studied in this paper. It is concluded that wind turbine efficiency is increased by 4%. •Wake recovery due to turbulence mixing is faster in two in line setup than single turbine.•Effect of blade rotation direction, counter and co rotating setups, is discussed in detail.•Downstream turbine is more efficient in counter-rotating than co-rotating setup.•Wake effect on the performance downstream turbine is investigated using fluid flow.•More wind energy is harvested from tip to middle than middle to root of the blade.