Fundamental aspects of the vortex flow on cones. Angular characterization of hyperlifting vortex torques; the law of filiation

This paper describes in detail the fundamental aspects of the vortex flow developed on the upper surface of a cone having an apex angle of 68.6°. It is one of a large number of studies carried out in the wind tunnel of the Valenciennes University aerodynamics and hydrodynamics laboratory whereby visualizations have enabled the flow of vortex structures to be monitored and consequently their development and positioning, under the influence of apex angles and at increasing angles of incidence, to be determined and defined. The existence and the preferential nature of intervortex angles are here confirmed and it has been found, by analogy with studies carried out on other types of slender bodies, that the law of filiation is applicable to the angular characterization of hyperlifting vortex torques and to the angular correspondence existing between their main and secondary structures. These findings suggest that there is a certain universality in the behaviour of these properties although no current theory would seem to be able as yet to provide a straightforward explanation of the phenomena.PACS Nos.: 44, 47