Design and commissioning of the laboratory-scaled model of a Troposkein VAWT for floating offshore applications

Abstract Vertical-axis wind turbines are attracting increasing interest for floating offshore applications due to several advantages over horizontal-axis turbines, including a lower center of gravity and simpler control requirements. A faster wake recovery compared to the one occurring in Horizontal Axis Wind Turbines is also reported in literature. To deepen the aerodynamic behavior of these wind turbines, a new prototype of Troposkein rotor was designed and commissioned at Politecnico di Milano. The experimental campaign is in progress in the wind tunnel over multiple operating conditions, including floating applications. This paper presents the commissioning tests carried on the scaled model showing among other operational characteristics, the wake recovery process down to 7.5 diameters downstream of the rotor in fixed-bottom configuration and for three tip speed ratios. Data will be used as reference case for the following analysis in floating conditions and will help to bridge the gap between numerical simulations and the current lack of experimental benchmarks. Computational fluid dynamics simulations were also performed at the optimal tip speed ratio identified experimentally. Comparisons of aerodynamic loads and wake characteristics at 1.5 and 3.5 rotor diameters downstream show excellent agreement between experimental measurements and numerical results.