  Vortex breakdown phenomena in the axial vortices is an important feature
which occurs frequently in geophysical flows (tornadoes and hurricanes) and in
engineering flows (flow past delta wings, Von-Kerman vortex dynamo). We analyze
helicity for axisymmetric vortex breakdown and propose a simplified
formulation. For such cases, negative helicity is shown to conform to the
vortex breakdown. A model problem has been analyzed to verify the results. The
topology of the vortex breakdown is governed entirely by helicity density in
the vertical plane. Our proposed methodology may be regarded as the prototype
for identifying and characterize the breakdowns/eye in more complicated
large-scale flows such as tornadoes/hurricanes.
