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High-order large-eddy simulations are performed to study the performance and flow fields of a ducted wind turbine operating at different tip speed ratios. To evaluate the effects of the duct, simulations with the same tip speed ratios are also performed on the corresponding open-rotor turbine. It is found that the ducted turbine consistently obtains higher power outputs than the open-rotor counterpart, and the duct itself enhances flow turbulence and blade trailing-edge vortices but weakens tip and hub vortices. Flow bifurcation is observed at the largest tip speed ratio and is identified to be caused by blade blockage effects. Comparative simulations are also performed on both turbines under different yaw angles. It is noticed that the ducted configuration is insensitive to small yaw angles and maintains higher power outputs than the open-rotor configuration at all yaw angles. Moreover, it is observed that the wakes of both configurations recover more quickly as the yaw angle increases.

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A high-order flux reconstruction method coupled with a high-order sliding mesh method is applied to analyze the performance of a ducted wind turbine at a Reynolds number of 1.25 × 10 6 . To investigate the impacts of the duct, axial flow simulations are also performed for the corresponding open-rotor turbine. It is shown that the ducted turbine has higher thrust and power outputs than the open rotor. Vorticity and velocity fields of two configurations are also visualized and analyzed to show the differences. To evaluate the effects of yawed flows, simulations are carried out for both turbines under five different yaw angles 𝛾 = 0 • , ±15 • , ±30 • . The results reveal that the ducted wind turbine has higher power outputs than the open counterpart at all tested yaw angles.