Vortex breakdown
From Glossary of Meteorology
vortex breakdown
The region of a vortex between a supercritical upstream flow incapable of supporting upstream-propagating centrifugal waves and a subcritical flow that allows downstream- propagating centrifugal waves.
The region is usually marked by abrupt swelling and often turbulence and reverse axial flow in the downstream side. Vortex breakdown is sometimes observed in tornadoes.
See hydraulic jump.
See hydraulic jump.