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## Main Question or Discussion Point

This is what I understand about Kelvin's Circulation Theorem

1)for inviscid (where the viscous forces are much LESS than inertial forces) AND uniform density flow, the circulation is conserved.

2)This implies (by some arduos vector calculus manipulations) that the vorticity of each fluid blob is conserved following the motion of each blob (ie 0 in this)...

NOW, this is what my notes say:

"When an aircraft wing starts to move, it sheds a vortex. But the total vorticity in the region must remain zero, by Kelvin's Circulation Theorem, so an opposite vortex is generated round the wing (this provides the swirl required to generate lift)."

So according to my notes, there are two opposite vortexes (whose vorticity sum equals zero) SEPARATED in space. So infact, vorticity is not locally conserved which is at odds with (2)...

Can anyone explain what I am not understanding?

Many thanks:)

1)for inviscid (where the viscous forces are much LESS than inertial forces) AND uniform density flow, the circulation is conserved.

2)This implies (by some arduos vector calculus manipulations) that the vorticity of each fluid blob is conserved following the motion of each blob (ie 0 in this)...

NOW, this is what my notes say:

"When an aircraft wing starts to move, it sheds a vortex. But the total vorticity in the region must remain zero, by Kelvin's Circulation Theorem, so an opposite vortex is generated round the wing (this provides the swirl required to generate lift)."

So according to my notes, there are two opposite vortexes (whose vorticity sum equals zero) SEPARATED in space. So infact, vorticity is not locally conserved which is at odds with (2)...

Can anyone explain what I am not understanding?

Many thanks:)