Abstract
We compare the decay of turbulence in superfluid 4 He produced by a moving grid to the decay of turbulence created by either impulsive spin-down to rest or by intense ion injection. In all cases, the vortex line density L decays at late time t as L∝t−3/2. At temperatures above 0.8 K, all methods result in the same rate of decay. Below 0.8 K, the spin-down turbulence maintains initial rotation and decays slower than grid turbulence and ion-jet turbulence. This may be due to a decoupling of the large-scale superfluid flow from the normal component at low temperatures, which changes its effective boundary condition from no-slip to slip.
Original language | English |
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Article number | 115303 |
Number of pages | 5 |
Journal | Physical Review Letters |
Volume | 115 |
Issue number | 15 |
DOIs | |
Publication status | Published - 8 Oct 2015 |
Keywords
- quantum turbulence
- homogeneous isotropic turbulence
- rotating turbulence
- grid turbulence
- dissipation
- superfluid helium
- zero temperature limit
- slip boundary conditions