Experimental study on drag-reduction mechanisms based on the physical characteristic of tip vortex

The drag-reduction mechanisms based on the physical characteristic of the tip vortex are investigated through experiments in the wind tunnel. Through 3DPIV (3D Particle Image Velocimetry) experiments, the physical characteristic of tip vortex is obtained, and the induced drag of wing is calculated based on the aerodynamic force measurement setup of wingtip proposed in this paper. Experimental results show that the non-dimensional circulation of the tip vortex increases with the increasing angle of attack and the wind speed. Meanwhile, with the decrease of the non-dimension circulation of the tip vortex or the increase of the spacing between the wing and the tip vortex, the induced drag becomes smaller and smaller. Specifically, the induced drag reduction can be achieved by inhibiting the non-dimensional intensity of the tip vortex, which weakens the interaction between the main wing and the tip vortex.