The turbulent drag force in superfluid .sup.3./sup.He−.sup.4./sup.He mixtures under oscillations of a quartz tuning fork

0563788 - FZÚ 2023 RIV RU eng J - Článek v odborném periodiku
Kapuza, S.S. - Chagovets, V. K. - Sokolov, S. S. - Vrakina, V. A. - Chagovets, Tymofiy
The turbulent drag force in superfluid ³He−⁴He mixtures under oscillations of a quartz tuning fork.
Low Temperature Physics. Roč. 47, č. 10 (2021), s. 805-811. ISSN 1063-777X. E-ISSN 1090-6517
Institucionální podpora: RVO:68378271
Klíčová slova: superfluid helium * superfluid mixtures He-3-He-4 * turbulence and laminar flows * quartz tuning fork
Obor OECD: Fluids and plasma physics (including surface physics)
Impakt faktor: 0.891, rok: 2021
Způsob publikování: Omezený přístup
https://doi.org/10.1063/10.0006059

We have studied the resonance curves of a quartz tuning fork of the fundamental frequency 32 kHz immersed in superfluid 4He and mixtures 3He–4He with 3He concentration of 5 and 15% in the temperature range of 0.35–2.5 K at saturated vapor pressure. Two types of experiments have been carried out, with a tuning fork both not covered by a bulb and coated by a bulb, i.e., in the restricted geometry. In both cases, the velocity-force dependences for the tuning fork showed a linear damping force at low peak velocities and extra drag due to the appearance of vortex lines accompanying the transition to turbulence under increasing peak velocity. These dependencies are mainly determined by the density of the normal helium component. There is a pronounced difference between superfluid 4He and mixtures of 3He in 4He, where 3He impurity particles provide a constant temperature-independent contribution to the normal component of the mixture.
Trvalý link: https://hdl.handle.net/11104/0335594