Improving the efficiency of a wind turbine using blades with winglets

Winglets are commonly used in aircraft to reduce induced drag and thus fuel costs. The efficiency of a winglet is related to its geometry (shape, orientation to the plane of the wing, flow regime on the wing). By extending the use of winglets to wind turbine blades, it is tried to estimate the improvement of their performances and to find the best geometry and configurations. That is why numerical investigations are carried out for several winglets configurations, for a turbulent flow regime. The RANS (Reynolds Averaged Navier-Stokes) model, combined with Realizable k-ε and SIMPLE algorithm are used as they have an acceptable computational cost and reasonable accuracy. In this research, the numerical analysis of two types of winglets is performed: (1) a winglet with two surfaces with a prescribed shape, with the seating angle varying with respect to the reference lifting surface and (2) a winglet with three surfaces, whose position is varied relative to the reference surface. The purpose of the numerical simulations is to obtain a useful configuration for a horizontal axis wind turbine that will be discussed in a forthcoming paper.