I wonder what is the difference between swirl and vorticity?

dear junseok kim,

vorticity is precisely defined to be the curl of the velocity vector. it represents the presence or absence of rotation in a flow field.

swirl is typically the azimuthal velocity in vortex filament like flow. usually if the swirl is present in a vortex filament (like a tornado), then the vorticity is also present. otherwise thay have no mathematical connection.

-vidyadhar mudkavi 30 october 2000

thanks a lot~