On a highly swept thin wing at incidence, flow separation over a blunt but slender body presents, when placed at a high angle to the wind, an organized structure characterized by two symmetrical and steady vortices. It is the case for an axisymmetrical ogee nose cone, on which the vortices (in white on the previous image) join up without being separated by a vortex-free median zone. Thanks to an illumination limited to a thin slit, it is possible to obtain a cross section view (the image shown here), where the flow is visualized by air bubble suspended in the water, and the vortices are highlighted by colored emissions.

Image created by Henri Werlé. Reproduced with permission from his spectacular collection Courants et Couleurs published in 1974 by ONERA, the French Aerospace Lab.