Workshop: Quantum Turbulence
Workshop on current problems in Quantum Turbulence: Thursday 14th
Organisers: J Vinen, A Golov, M Tsubota
| Time | Topic | |
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| 14:00 |
Session 1: Decay of QT at very low temperatures |
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Introduction
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Status of existing measurements on the decay of QT at very low temperatures |
(i) summary; Eltsov | |
| (ii) Discussion with comments by Walmsley, Ihas, Tsepelin, Yano, Skrbek, Vinen ... | ||
Status of present theory (quasi-classical & quantum cascades, crossover region, bottleneck, reconnections, fractal nature of the tangle, losses in 3He and 4He) |
(i) summary; Kozik |
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| (ii) summary; Barenghi | ||
| (iii) Discussion | ||
(vortex filament & GP calculations) |
(i) summary; Tsubota | |
| (ii) Discussion: Hänninen | ||
Future & sum up
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Coffee break [time to be confirmed by chair] Coffee and Tea will be served between 15:30 and 16:30
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Session 2: Generation of QT by oscillating structures
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| Ladislav Skrbek (Prague): General introduction |
a) short overview on various oscillating structures: discs, grids, spheres, wires, forks used in cryogenic environment |
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b) introduction to transition from laminar to turbulent drag regime in flow due to oscillating structures in classical fluids, drag coefficient |
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c) transition to turbulent drag regime in He II and its analysis in terms of the drag coefficient |
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| d) critical velocities in He II, scaling |
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| Hideo Yano (Osaka) | Critical phenomena of quantum turbulence generated by a vibrating wire in superfluid 4He |
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| Louise Wheatland (Lancaster) | Anomalous behaviour of quartz tuning forks in superfluid 4He at low temperatures |
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| Shaun Fisher (Lancaster) Introduction to 3He |
a) Vibrating objects in 3He - wires, forks, grids - an overview |
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| b) Andreev reflection | ||
| Martin Jackson (Lancaster) | Turbulence detection using quartz tuning forks in superfluid 3He at very low temperatures |
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| Yusuke Nago (Osaka) | Onset velocity for vortex emission induced by wire vibration in superfluid 3He-B |
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| Rob de Graaf (Helsinki) | Quartz tuning fork signals in rotating 3He-B at temperatures below 0.3 Tc |
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| S. Fujiyama (Osaka) | Numerical simulations of a force on an oscillating object driven by a superfluid |
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Session 3: Visualization of quantum turbulence Chaired by: Steve Van Sciver and Yuri Sergeev
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Experimental and theoretical introductions by Steve Van Sciver and Yuri Sergeev followed by short contributions by Matthew Paoletti, Dan McKinsey, Shaun Fisher and M Kobayashi |
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Short contributions (time permitting)
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| Juha Tuoriniemi (Helsinki) | Forks: ultra high Q-values, effect of finite compressibility
and acoustic resonances in He II and helium mixtures |
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| Peter Skyba (Kosice) | Comments on electronics aspects of measurement of
vibrating structures |
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| John Owers-Bradley/ Chris Mellor (Nottingham) | On technological aspects of nanomechanical resonators |
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| 18:00 |
Close workshop
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