Entrainment effects in vortex flows

Following recent work of the present author [Phys. Fluids 6, 1524 (1994)], the effects of entrainment of axisymmetric vortex flows are further investigated. Assuming self-similar flow, it is found that, under the influence of entrainment, vortex flows with jet-like cores always approach certain critical flow states, and self-similar solutions cease to exist afterward. It is argued that this apparent paradox can be resolved by accounting for the possibility of vortex breakdown. Furthermore, explanations are presented for the possible appearance of successive vortex breakdown transitions and for the increasingly jet-like character of certain subcritical vortex flows as they approach a cross section of critical flow.