Sources of asymmetric flow over the blunt-nose slender body

The pattern of asymmetric vortices over a blunt-nose slender body is manageable and highly dependent on the location of artificial microperturbation (AMP) on the nose at a high angle of attack (AoA). A particle is introduced and attached to the nose surface to examine the mechanism of asymmetric flow induced by AMP at high AoA (α = 50°). Wind tunnel experiments and numerical simulations were conducted to investigate the mechanism of asymmetric flow generated over the blunt-nose slender body. Perturbation flow (PF), which is separated from the AMP surface, divides the shear layer separating from the nose of the slender body into two parts (long and short). The shear layer separating is shown as separation line. The long part on the opposite side with AMP rolls up a vortex earlier than the short one on the same side with AMP. Moreover, the vortex from the long part exhibits higher vorticity than that from the short one. The differences in the two parts result in asymmetric vortices over the blunt-nose body at high AoA. The PF develops into the opposite side with AMP, thereby increasing the asymmetry of flow. The associated flow separation and evolution of streamlines are discussed in detail.