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Abstracts
P3.18
Small-scale universality of particle dynamics in turbulent flows of He
II
La Mantia Marco, ˇSvanˇcara Patrik, Duda Daniel, Rotter Miloˇs, Skrbek Ladislav
Faculty of Mathematics and Physics, Charles University, Ke Karlovu 3, 121 16
Prague, Czech Republic
The flow-induced motions of small particles suspended in He II are investigated
experimentally, by visualization, above 1 K. We show that the statistically
described particle dynamics does not depend on the type of imposed two-fluid
flow, at scales smaller than the average distance between quantized vortices.
Regardless of the mechanically or thermally driven nature of the large-scale flow,
the tails of the observed particle velocity distributions display the same power-law
shape. This property of quantum turbulence can be seen as analogous to the
small-scale universality reported to occur in classical turbulent flows of viscous
fluids. We acknowledge the support of GA ˇCR 16-00580S.
P3.19
Coupled dynamics for superfluid He4 in the channel.
Khomenko Dmytro, Mishra Pankaj, Pomyalov Anna
Weizmann Institute of Science, Department of Chemical Physics, Rehovot Israel
We present the results for the coupled dynamics of normal and superfluid
components of the superfluid He4 in the channel. We consider the case of
the counterflow turbulence with laminar normal component. In particular, we
calculated profiles of the normal velocity, the mutual friction and the vortex line
density, as well as other flow properties and compared them to the case when the
dynamic of the normal component is “frozen”. We have found that the coupling
between the normal and superfluid components leads to a flattening of the normal
velocity profile, increasingly more pronounced with temperature as the mutual
friction, and therefore coupling, become stronger. The commonly measured flow
properties also change when the coupling between two components is taken into
account.
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