Energy cascade and the four-fifths law in superfluid turbulence

• Published in: Europhysics letters Vol. 97; no. 3; p. 1
• Main Authors: Salort, J, Chabaud, B, Leveque, E, Roche, P-E
• Format: Journal Article
• Language: English
• Published: 01-02-2012
• Subjects: Cascades; Computational fluid dynamics; Fluid flow; Fluids; Mathematical models; Superfluidity; Turbulence; Turbulent flow
• ISSN: 0295-5075; 1286-4854

The 4/5-law of turbulence, which characterizes the energy cascade from large to smallsized eddies at high Reynolds numbers in classical fluids, is verified experimentally in a superfluid ...He wind tunnel, operated down to 1.56K and up to R ... 1640. The result is corroborated by high-resolution simulations of Landau-Tisza's two-fluid model down to 1.15 K, corresponding to a residual normal fluid concentration below 3% but with a lower Reynolds number of order R ... 100. Although the Karman-Howarth equation (including a viscous term) is not valid a priori in a superfluid, it is found that it provides an empirical description of the deviation from the ideal 4/5-law at small scales and allows us to identify an effective viscosity for the superfluid, whose value matches the kinematic viscosity of the normal fluid regardless of its concentration. (ProQuest: ... denotes formulae/symbols omitted.)