Berlin 2018 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 77: Focus Session: Quantum Turbulence and Imaging of Quantum Flow of Superfluids

TT 77.5: Hauptvortrag

Donnerstag, 15. März 2018, 11:45–12:15, H 0104

Visualization of Superfluid Helium Flows — •Marco La Mantia — Faculty of Mathematics and Physics, Charles University, Prague, Czech Republic

The investigation of flows of superfluid helium (He II) constitutes an active and challenging research field. Flow visualization techniques, which allow following the motion of relatively small particles suspended in the fluid, have been specifically giving in recent years significant contributions to our understanding of the underlying physics. It has been shown, for example, that the derived flow-induced properties, such as the velocity statistical distribution, depend on the length scale probed by the particles, for both thermally and mechanically driven flows of He II. Quantum features appear indeed at small enough length scales, smaller than the quantum length scale of the flow, the average distance between quantized vortices, while, at larger scales, a classical (viscous-like) picture emerges, especially in the case of mechanically driven flows. The visualization results obtained to date firmly support the view that the investigation of particle dynamics in quantum flows is not only interesting in its own right but it may also lead to the deeper understanding of fluid turbulence in general.

The author thanks L. Skrbek, M. Rotter, D. Duda, E. Varga, P. Švančara and P. Hrubcová for fruitful discussions and valuable help; the support of the Czech Science Foundation under grant GAČR 16-00580S is acknowledged.