Wind Tunnel Testing of Wind Turbines and Farms

This chapter reviews the wind tunnel testing of scaled wind turbines and farms, which in recent years is finding an increased interest by the scientific community for aerodynamic, aeroelastic and control applications. The chapter starts by reviewing the fundamental scaling laws, which reveal the quantities that need to be matched between full-scale system and scaled model for similarity to hold. The scaling requirements are then combined with the additional constraints due to physics, manufacturing, actuation and instrumentation, leading to a best compromise design of the scaled model for a given application. The analysis highlights that a scaled model cannot in general be an exact and complete replica of its full-scale counterpart. Nonetheless, sophisticated scaled experimental setups characterized by a significant realism can be developed for a plethora of different complex applications, in support of physical understanding, model validation and calibration, and the low-cost low-risk testing of new ideas and concepts. The chapter is concluded with an overview of turbine and farm experiments developed by the authors.