Dissipation by pinned vortex lines in the superfluid helium film

Journal Article · Thu Sep 01 04:00:00 EDT 1977 · J. Low Temp. Phys.; (United States)

DOI:https://doi.org/10.1007/BF00661445· OSTI ID:7290603

Harris-Lowe, R F

The status of theoretical and experimental work on dissipation in the helium film is reviewed, and it is concluded that there does not yet exist a satisfactory theoretical interpretation of dissipation in the film which can account for the complete range of observed phenomena below the superfluid transition temperature T/sub lambda/. Although the most recent theory, which accounts for dissipation in terms of intrinsic fluctuations in the flow, has been successful in a temperature interval just below T/sub lambda/attempts to extend the theory to include all temperatures below T/sub lambda/have not met with the same degree of success. A new model is proposed which accounts for dissipation in superfluid helium film transport in terms of the continuous generation of pinned vortex lines. In principle, this model is similar to one advanced by Vinen, involving the growth and decay of a tangled array of vortex lines. Qualitatively, it is shown that the present mechanism can account for many of the phenomena observed in helium film transport experiments at temperatures well below the lambda transition. For example, sharp changes in the flow rate are associated with changes in the number of pinned vortex lines. In addition, the theory predicts that at superfluid stream velocities v/sub s/ that just barely exceed the critical velocity v/sub c0/ for the appearance of dissipation, the rate of dissipation Q is given by Q=AN(v/sub s/-v/sub c0/)/sup 3/2/ where N is the number of pinned vortex lines, and A is a constant determined by the vortex line parameters. The value of 3/2 for the exponent is a clear prediction of the theory, and it represents the first precise, numerical prediction by any theory of a physical quantity which is associated with dissipation in the helium film, and which can be measured experimentally.

• Research Organization: Department of Physics, Royal Military College, Kingston, Ontario, Canada
• OSTI ID: 7290603
• Journal Information: J. Low Temp. Phys.; (United States), Journal Name: J. Low Temp. Phys.; (United States) Vol. 28:5; ISSN JLTPA
• Country of Publication: United States
• Language: English

Related Subjects

640450* -- Fluid Physics-- Superfluidity
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
CRYOGENIC FLUIDS
DOCUMENT TYPES
ELEMENTS
ENERGY LOSSES
FILM FLOW
FLUID FLOW
FLUIDS
HELIUM
LAMBDA POINT
NONMETALS
PHYSICAL PROPERTIES
RARE GASES
REVIEWS
SUPERFLUIDITY
THERMODYNAMIC PROPERTIES
TRANSITION TEMPERATURE
VELOCITY
VORTEX FLOW