Taking the three-dimensional horizontal axis tidal current turbine as the initial model, the influence of the winglet twist angle on the hydrodynamic performance and wake characteristics of the tidal current turbine is analyzed by CFD numerical calculation, and the influence mechanism of the winglet's twist angle on the hydrodynamic performance of the turbine blade is clarified. The results show that the change of the winglet twist angle has a significant impact on the hydrodynamic performance of the tidal current turbine. Compared with the initial model, when winglet twist angle is -6°, the power coefficient of the tidal current turbine increases by 5.17% and the drag coefficient increases by 7.01%. In the range of twist angle from -9° to 6°, the power coefficient with winglet first increases and then decreases with the increase of twist angle, while the drag coefficient decreases monotonously. The changes of the winglet twist angle significantly affect the radial flow state of the fluid immediate behind the blade tip of the turbine, affect the tip loss and the surface pressure distribution, and then change the hydrodynamic performance of the tidal current turbine. By comparing the power spectrum density curve of velocity fluctuation, it can be seen that the winglet's twist angle will affect the axial velocity fluctuation of blade tip vortex, and the influence will gradually decrease with the increase of axial distance, but the influence on radial velocity fluctuation is not obvious.

tidal energy  /  numerical simulation  /  hydrodynamics  /  hydraulic turbine  /  winglet  /  power spectral density