An Experimental Investigation on the Wake Characteristics behind a Novel Twin-Rotor Wind Turbine

An experimental study was performed to examine the wake characteristics and aeromechanic performance of an innovative twin-rotor wind turbine (TRWT) in comparison with those of a conventional single-rotor wind turbine (SRWT). The comparative study was conducted in a large-scale Aerodynamic/Atmospheric Boundary Layer (AABL) wind tunnel with the TRWT and SRWT model sited in simulated atmospheric boundary layer (ABL) winds under neutral stability conditions. In addition to measuring the power outputs of the TRWT and SRWT models, dynamic wind loads acting on the wind turbine models were also investigated in detail. Furthermore, a high-resolution PIV system was used for detailed wake flow field measurements (free-run and phase-locked) in order to quantify the characteristics of the turbulent turbine wake flows and to quantitatively visualize the transient behavior of the unsteady vortex structures behind the wind turbine models. The detailed flow field measurements are correlated with the dynamic wind loads and power output measurements to elucidate the underlying physics for higher total power generation and better durability of the wind turbines.