The axisymmetric vortex breakdown phenomenon

The paper reviews the recent theoretical studies of the author and co-workers on the axisymmetric vortex breakdown phenomenon. The theory is built of a, global analysis of the steady Euler equations which describe the motion of all axisymmetric and inviscid swirling flow in a pipe and of linear stability analyses of the various steady-state solutions. Asymptotic studies are also used to explore the effects of viscosity, pipe divergence, and inlet vorticity perturbations on the flow behavior. It is shown that the present study provides a consistent explanation of the physical mechanism leading to the axisymmetric vortex breakdown phenomenon as well as the conditions for its occurrence. Calculations of the breakdown conditions of various vortices in a pipe as well as of the leading-edge vortices above slender delta wings are also summarized.