 Andronikashvili experiment

Closely spaced disks undergo torsional oscillations in He-II. Viscous entrainment of the normal component contributes a temperature-dependent moment of inertia, while vortex-free superfluid need not rotate with the disks. The interpretation requires the normal component to follow the drive under the apparatus's spacing and frequency conditions. The experiment is associated with Elephter Andronikashvili.