The flow structure induced by plane and cylindrical shell delta winglet

trapezoidal winglet and rectangular winglet vortex generators(VGs)is investigated with the particle image velocimetry(PIV)to obtain the velocity and vorticity fields.A small rectangular wind tunnel is built to carry out experiments at Reynolds number Re=700 and attack angle α=60°.The results show that the vortex structure of plane and cylindrical shell delta winglets is mainly distributed in the central area of the inclination edge and the corner area of the trailing edge of the VG. For trapezoidal and rectangular winglets

vortices mainly distribute in the wing tip region of the leading edge area and the trailing edge area.Besides

the cylindrical shell trapezoidal winglet induces a central area vortex structure

which has the largest influential area among all types of VGs.The vortex structure induced by the leading edge of trapezoidal and rectangular winglets is generally stronger than that by trailing edge area.As the flow goes on

the strength of vortex structures degrades.Only one main vortex can be maintained along the flow direction in the case of a delta winglet

while one main vortex and one trailing edge corner vortex can be identified in a trapezoidal and rectangular winglet.The vortex structure induced by plane shell winglet tends to get away from the bottom wall

while the vortex structure induced by a cylindrical shell winglet tends to maintain close to the bottom wall.