course: Quantum turbulence: turbulence in a superfluid
speaker: William Frank Vinen (University of Birmingham, UK)abstract: An understanding of various forms of turbulence in classical fluids continues to attract intense interest, in spite of very many years of experimental and theoretical study. Turbulence provides physicists, applied mathematicians and engineers with many theoretical challenges, relating to its concern with non-linear dynamics, and it is of course of enormous practical importance. Turbulence in a superfluid differs from that in a classical fluid because the flow of a superfluid is strongly influenced by quantum effects: such turbulence is therefore often described as quantum turbulence. The study of quantum turbulence therefore combines the challenges provided by classical turbulence with those associated with conventional condensed matter physics, where quantum effects are often of the greatest importance.
The lectures will aim first to provide the necessary background in both classical fluid mechanics and the phenomenon of superfluidity. The early discovery of turbulence associated with heat flow in superfluid 4He, which has no classical analogue, will be described, along with the development of our understanding of it. This will be followed by more detailed accounts of recent work that has tended to focus on the way in which well-known forms of classical turbulence are modified when the classical fluid is replaced by a superfluid, which may be the superfluid phase of either 4He or 3He. It will be shown how, as one might expect, the modification can be quite small on large length scales, but how quantum effects can have a strong effect on small-scale motion. Classical turbulence is always dissipated ultimately by viscosity, and the dissipative mechanisms that replace viscosity in an inviscid superfluid will be discussed.
timetable:
Tue 10 Jul, 9:00 - 10:30, Aula Dini
Wed 11 Jul, 9:00 - 10:30, Aula Dini
Thu 12 Jul, 9:00 - 10:30, Aula Dini
documents:
1.mpg.mpeg
k2.mpg
pendmovie9.mpg
Pisa2007.ppt
vor5.mpg
vor6.mpg
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