Effect of Vortex Generators on Transonic Swept Wings

This paper examines the effects of corotating blade-type vortex generators on transonic sweptback wings using computational fluid dynamics studies. Infinite-span (two-dimensional) swept wings are first considered to understand the basic physics of vortex generators. Sweep angles are given virtually to the wings by changing the freestream direction. Vortex generators are placed on the wings, and the visualized interactions of their tip vortices with the boundary layer reveal the relationship between the effect of the vortex generators and the wing sweep angle. The physics of vortex-generator tip vortices are then described to explain how vortex generators on swept wings efficiently suppress shock-induced separation by mixing boundary layers. It is also shown that the vortex-generator angle of incidence to the local flow can slightly improve the effect of the vortex generators but that wing sweep angle has a greater influence on their effect. Based on the discussion of infinite-span wings, the computational results of the NASA Common Research Model with and without vortex generators are finally examined and compared with the experiment. It is confirmed that toe-out vortex generators on the three-dimensional Common Research Model are as efficient as those on an infinite-span wing with a moderate sweep angle.