Large-eddy simulations of turbulent flows in arrays of helical- and straight-bladed vertical-axis wind turbines

• Published in: Journal of renewable and sustainable energy Vol. 15; no. 6
• Main Authors: Gharaati, Masoumeh, Wei, Nathaniel J., Dabiri, John O., Martínez-Tossas, Luis A., Yang, Di
• Format: Journal Article
• Language: English
• Published: Melville American Institute of Physics 01.11.2023; American Institute of Physics (AIP)
• Subjects: actuator line model; Arrays; Bending fatigue; Bending moments; Flow characteristics; Large eddy simulation; Maintenance costs; Statistical analysis; sustainable energy; turbulence simulations; turbulent flows; vertical axis wind turbine; Vertical axis wind turbines; Vortices; Wind effects; WIND ENERGY; Wind power; wind turbines
• ISSN: 1941-7012; 1941-7012
• DOI: 10.1063/5.0172007

Effects of helical-shaped blades on the flow characteristics and power production of finite-length wind farms composed of vertical-axis wind turbines (VAWTs) are studied numerically using large-eddy simulation (LES). Two helical-bladed VAWTs (with opposite blade twist angles) are studied against one straight-bladed VAWT in different array configurations with coarse, intermediate, and tight spacings. Statistical analysis of the LES data shows that the helical-bladed VAWTs can improve the mean power production in the fully developed region of the array by about 4.94 % – 7.33 % compared with the corresponding straight-bladed VAWT cases. The helical-bladed VAWTs also cover the azimuth angle more smoothly during the rotation, resulting in about 47.6 % – 60.1 % reduction in the temporal fluctuation of the VAWT power output. Using the helical-bladed VAWTs also reduces the fatigue load on the structure by significantly reducing the spanwise bending moment (relative to the bottom base), which may improve the longevity of the VAWT system to reduce the long-term maintenance cost.