Control characteristics of vortex-generator height on asymmetric flow over a blunt-nose body

The study investigates the control characteristics of vortex-generator (VG) on asymmetric flow over a blunt-nose body at a high angle of attack by introducing the key parameter of height ratio (h/D), in which h stands for the height of VG and D is the diameter of the slender body. The results indicate that the two asymmetric vortex patterns emerge at different heights. When a VG of small h/D is applied to the nose, it induces flow acceleration, allowing the flow to acquire additional energy. This results in delayed flow separation and the formation of a low vortex on the VG side. As the height ratio of the vortex-generator increases, the flow ceases to gain energy from the VG and instead encounters an energy loss attributed to the obstructive impact of the VG. Furthermore, the augmentation of the VG-induced vortex results in the curvature of spatial streamlines downstream, leading to an earlier separation of the main vortex on the VG side. Consequently, an asymmetric vortex pattern, distinct from that observed at small h/D, is evident on the leeward side, characterized by a high vortex on the VG side. The characteristics of associated side forces, pressure distributions, and flow fields with the increasing h/D are presented in detail.