REVISED THEORY OF VORTEX RINGS - A SIMPLIFIED REVIEW OF THE STATE-OF- THE-ART

The vortex ring is an essential and ubiquitous phenomenon that has been rather neglected in aerodynamics and technology, perhaps because it is usually construed, unfortunately, as a mere exercise in old-fashioned mathematics. The existing venerable theories of this phenomenon are at once little known, difficult, uncoordinated, insufficient and inconsistent. They are reviewed, modified and combined, and are thus made ready for the long-overdue experimental tests. An essential mathematical preliminary, the theory of straight vortices, is discussed.