Experimental Investigation of the Cooperation of Wind Turbines

• Published in: Energies (Basel) Vol. 15; no. 11; p. 3906
• Main Authors: Wiklak, Piotr, Kulak, Michal, Lipian, Michal, Obidowski, Damian
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 01-06-2022
• Subjects: Alternative energy sources; Atmospheric boundary layer; Efficiency; Electric power; Electricity distribution; Energy industry; Energy resources; experimental aerodynamics; Farm buildings; Flow velocity; Fluid flow; Gusts; horizontal-axis wind turbine (HAWT); Maintenance costs; Pitch (inclination); Renewable resources; Reynolds number; small wind turbine (SWT); Tip speed; Turbines; Turbulence; Turbulence intensity; Upstream; wind farm; Wind farms; Wind power; wind tunnel; Wind tunnels; Working conditions; Yaw
• ISSN: 1996-1073; 1996-1073
• DOI: 10.3390/en15113906

The article discusses the wind tunnel experimental investigation of two turbines (the downstream unit placed fully in the wake of the upstream one) at various turbulence intensity levels and wind turbine separation distances, at a Reynolds number of approximately 105. The velocity deficit due to the upstream turbine operation is reduced as the wake mixes with the undisturbed flow, which may be enhanced by increasing the turbulence intensity. In a natural environment, this may be provoked by natural wind gusts or changes in the wind inflow conditions. Increased levels of turbulence intensity enlarge the plateau of optimum wind turbine operation—this results in the turbine performance being less prone to variations of tip speed ratio. Another important set of results quantifies the influence of the upstream turbine operation at non-optimal tip speed ratio on the overall system performance, as the downstream machine gains more energy from the wake flow. Thus, all power output maximisation analyses of wind turbine layout in a cluster should encompass not only the locations and distances between the units, but also their operating parameters (TSR, but also pitch or yaw control of the upstream turbine(s)).