EMP is funded through the Horizon2020 programme of the European Commission.
Selected Publications

Crossover from hydrodynamic to acoustic drag on quartz tuning forks in normal and superfluid 4He

D.I. Bradley, M. Clovecko, S.N. Fisher, D. Garg, E. Guise, R.P. Haley, O. Kolosov, G.R. Pickett, V. Tsepelin, D. Schmoranzer, L. Skrbek

We present measurements of the drag forces on quartz tuning forks oscillating at low velocities in normal and superfluid 4He. We have investigated the dissipative drag over a wide range of frequencies, from 6.5 to 600 kHz, by using arrays of forks with varying prong lengths and by exciting the forks in their fundamental and first overtone modes. At low frequencies the behavior is dominated by laminar hydrodynamic drag, governed by the fluid viscosity. At higher frequencies acoustic drag is dominant and is described well by a three-dimensional model of sound emission.

Phys. Rev. B 85, 014501 (2012)

doi: 10.1103/PhysRevB.85.014501