Abstract. This paper describes the methodology that was followed for designing a scaled wind turbine model. This model is intended to be used in complex terrain studies as well as deep array wind farm control tests. Therefore, emphasis was given on making it as compact as possible while keeping a high level of instrumentation. The result is a three blade wind turbine with rotor diameter of 0.6 m equipped with active pitch, yaw and torque control. After a discussion on the design procedure, we present preliminary performance characteristics of the model obtained experimentally.
IntroductionWind tunnel testing is an invaluable tool for improving wind turbine efficiency and eventually reducing the levelized cost of energy from wind. The wind turbine component that has benefited the most from wind tunnel testing is certainly the blade, since wind tunnel testing of wind turbine airfoils was used from the very beginning of the wind energy industry [1]. However, wind tunnel testing embraced over the years more aspects of wind turbine design, going one step further from airfoil performance experiments to testing of scaled wind turbine models. Indeed, wind tunnel testing of scaled wind turbines has been used for a plethora of applications such as wake studies [2,3], wind turbine control tests [4], wind farm control validation [5] and complex terrain studies [6]. Undoubtedly, scaled wind turbine model design evolved over the years following the demand for new research applications. For example, in the MEXICO project [2, 3] a 4.5 m diameter wind turbine model was developed with highly instrumented blades with the purpose of creating a database of wake and rotor load data. In other wake studies smaller scaled wind turbines were used, such as the 10 cm diameter model that Chamoro et al. used in [7] or the 15 cm model developed by Bastankhah in [8]. Models of similar size have been used for simulating wind farms in a wind tunnel, as for example the nine scaled models of 12 cm rotor diameter used for simulating a 3×3 array in [9]. In [4], an aeroelastically scaled model of a Vestas V90 wind turbine was developed, featuring a 2 m rotor diameter and active torque, yaw and individual pitch control. In [5], a model with similar control capabilities but a smaller rigid rotor (1.1 m diameter) and flexible tower was developed.The above list, although not exhaustive, reveals the great diversity of scaled wind turbine models that exist in the literature. Some of them are quite sophisticated in terms of design and instrumentation, yet their size requires large wind tunnels and/or limits the number of wind turbines that can be used to avoid blockage or other undesirable effects. Some others are quite small and, despite being very useful for wind farm aerodynamic studies, they have limited capabilities and/or aerodynamic performance. In this paper we introduce a multipurpose scaled