ENTRAINMENT EFFECTS IN VORTEX FLOWS

Following recent work of the present author [Phys. Fluids 6, 1524 (199 4)], the effects of entrainment of axisymmetric vortex flows are furth er investigated. Assuming self-similar flow, it is found that, under t he influence of entrainment, vortex flows with jet-like cores always a pproach certain critical flow states, and self-similar solutions cease to exist afterward. It is argued that this apparent paradox can be re solved by accounting for the possibility of vortex breakdown. Furtherm ore, explanations are presented for the possible appearance of success ive vortex breakdown transitions and for the increasingly jet-like cha racter of certain subcritical vortex flows as they approach a cross se ction of critical flow.