In this research work, we investigated a diffuser augmented wind turbine's performance or better known as a wind lens. The wind lens consists of a circular flanged diffuser and a horizontal axis wind turbine with a diameter of 0.6 m. The diffuser length to the diameter ratio is 0.226, and the flange height to diameter ratio is 0.1. The performance of the wind Lens is investigated numerically by solving the flow field using Reynolds Averaged Navier-Stokes for incompressible flow. The finding of this work shows that the flange's role is significant to the performance; also, it shows that the opening angle of the diffuser is essential if the rotation speed of the turbine is set wisely. The wind lens's output torque at an inlet speed of 5 m/s is superior to the bare turbine by 30-60%, which shows the wind lens's usefulness at low wind speed.
Keywords: Wind lens, Wind turbine aerodynamics, Flanged diffuser, DAWT.