RANS simulations of the stepped duct effect on the performance of ducted wind turbine

• The stepped duct wind turbine performance compared to the simple-ducted one.
• The numerical procedure got verified using the experimental data.
• The best position for the step in the duct was investigated.
• The interaction of the wind turbine and the stepped duct was also investigated.
• A higher performance has been achieved by using stepped duct instead of simple one.

With the rise in oil price and population growth, renewable energies are assumed to be the main source of energies for the next generation. Wind as a natural, eco-friendly and renewable source of energy has been at the center of concentration for decades. Recently there has been some ideas regarding the self-regulating urban wind turbines. Researchers have shown that a proper enclosure increases the wind velocity and therefore more torques can be exerted on the rotors, therefore more power can be generated. These enclosures are light and cheap, therefore they are applicable and effective. In the present study, an enclosure was modified to increase the exerted torque with implementing a step at the outlet region of the enclosure. Comparison between the stepped and simple duct indicates the significance of the step role on the wind profile inside the enclosure. In order to find the proper position of the turbine inside the enclosure, three different locations for the turbine inside the enclosure were investigated and it was found that placing the turbine at inlet section of the enclosure has the most power coefficient. In the present case, implementing this simple step has increased the power coefficient by approximately 16%.