- #1
SunSmellsLoud
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Suppose you have a bucket filled with superfluid Helium-4 and you spin it with a large angular velocity Ω, the bucket obviously has angular momentum.
Spinning fast enough, the fluid develops irrotational vortex lines which carry quanta of angular momentum, while leaving the curl of the ∇xv 0, as it should be (with v the microscopic velocity field).
My question is, supposing you start with the bucket at rest, it's obvious that the fluid has no angular momentum, but considering the fact there is no friction between the bucket and the fluid, how does the superfluid get the angular momentum needed to produce vortex lines?
Spinning fast enough, the fluid develops irrotational vortex lines which carry quanta of angular momentum, while leaving the curl of the ∇xv 0, as it should be (with v the microscopic velocity field).
My question is, supposing you start with the bucket at rest, it's obvious that the fluid has no angular momentum, but considering the fact there is no friction between the bucket and the fluid, how does the superfluid get the angular momentum needed to produce vortex lines?