Comparative analysis of bent and basic winglets on performance improvement of horizontal axis wind turbines

The winglet has been widely deployed in the optimization of the blade design as it reduces the tip loss of the blade and increases the swept area of the rotor. However, previous studies have not adequately investigated the effect of platform motion on winglet performance in wind turbines. The objective of this study is to propose a novel bent winglet structure for wind turbines to improve performance under both stationary and surge conditions. To achieve this, the NREL Phase VI horizontal axis wind turbine (HAWT) is treated as a baseline. The numerical method employed is validated by comparing the simulated power and pressure coefficients of the HAWT with experimental data from the literature. The performance of the conventional winglet with the proposed novel winglet is compared in detail, taking into account the cant, twist, expansion direction, length, and winglet number of the conventional winglet. The results show that the novel bent winglet exhibits superior performance, with a 14.5% improvement in performance compared to the conventional winglet under surge motion. This study provides a feasible scenario for the optimization of onshore and offshore wind turbine designs. •The overall performance with different winglets is analyzed.•An advanced bent winglet is proposed to maximize power gain of 14.5%.•The aerodynamic performance of winglets is compared at different wind speeds.•The performance of the winglets under surge motion is also explored.