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Session: Superfluids 2

Session starts: Wednesday 26 August, 13:30

Presentation starts: 14:30

Room: Room E

*Philippe-E. Roche (Institut Néel, CNRS / Univ. Grenoble Alpes)*

Simone Babuin (Institute of Physics ASCR, Prague)

Emmanuel Lévêque (LMFA, Ecole Centrale de Lyon / CNRS)

Emil Varga (Faculty of Mathematics and Physics, Charles University, Prague)

Abstract:

The typical spacing between superfluid vortices in an isothermal turbulent tangle is proportional to the integral scale H rescaled by the quantum Reynolds number Re_K=H.V/K to the power of 3/4, where K is the quantum of circulation around of single vortex [Salort et al.,EPL 2011]. This empirical relation can be seen as the quantum-turbulence version of the corresponding well-know equation giving Kolmogorov dissipative scale in classical turbulence. In 2014, we studied the temperature dependence of the numerical factor (d/H).Re_K^{3/4} in 4He by joint numerical and experimental analysis of steady state turbulence over a wide temperature interval (1.2 - 2.16 K) [Babuin et al., EPL 2014]. Agreement between the two analyses was found good except at the very ends of this temperature interval. We will discuss this issue by presenting additional experimental data obtained by post-processing of superfluid experiments published between 1975 and 1998.

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*Philippe-E. Roche, Simone Babuin, Emmanuel Lévêque, Emil Varga*

14:30

15 mins

Inter-vortex spacing in superfluid turbulence : temperature and Reynolds number dependences
15 mins

Session starts: Wednesday 26 August, 13:30

Presentation starts: 14:30

Room: Room E

Simone Babuin (Institute of Physics ASCR, Prague)

Emmanuel Lévêque (LMFA, Ecole Centrale de Lyon / CNRS)

Emil Varga (Faculty of Mathematics and Physics, Charles University, Prague)

Abstract:

The typical spacing between superfluid vortices in an isothermal turbulent tangle is proportional to the integral scale H rescaled by the quantum Reynolds number Re_K=H.V/K to the power of 3/4, where K is the quantum of circulation around of single vortex [Salort et al.,EPL 2011]. This empirical relation can be seen as the quantum-turbulence version of the corresponding well-know equation giving Kolmogorov dissipative scale in classical turbulence. In 2014, we studied the temperature dependence of the numerical factor (d/H).Re_K^{3/4} in 4He by joint numerical and experimental analysis of steady state turbulence over a wide temperature interval (1.2 - 2.16 K) [Babuin et al., EPL 2014]. Agreement between the two analyses was found good except at the very ends of this temperature interval. We will discuss this issue by presenting additional experimental data obtained by post-processing of superfluid experiments published between 1975 and 1998.