Energy spectra of finite temperature superfluid helium-4 turbulence

Journal Article · Wed Oct 15 04:00:00 EDT 2014 · Physics of Fluids (1994)

DOI:https://doi.org/10.1063/1.4898666· OSTI ID:22310807

Kivotides, Demosthenes ^[1]

---

1. Department of Aeronautics, Imperial College London, London SW7 2AZ (United Kingdom)

A mesoscopic model of finite temperature superfluid helium-4 based on coupled Langevin-Navier-Stokes dynamics is proposed. Drawing upon scaling arguments and available numerical results, a numerical method for designing well resolved, mesoscopic calculations of finite temperature superfluid turbulence is developed. The application of model and numerical method to the problem of fully developed turbulence decay in helium II, indicates that the spectral structure of normal-fluid and superfluid turbulence is significantly more complex than that of turbulence in simple-fluids. Analysis based on a forced flow of helium-4 at 1.3 K, where viscous dissipation in the normal-fluid is compensated by the Lundgren force, indicate three scaling regimes in the normal-fluid, that include the inertial, low wavenumber, Kolmogorov k{sup −5/3} regime, a sub-turbulence, low Reynolds number, fluctuating k{sup −2.2} regime, and an intermediate, viscous k{sup −6} range that connects the two. The k{sup −2.2} regime is due to normal-fluid forcing by superfluid vortices at high wavenumbers. There are also three scaling regimes in the superfluid, that include a k{sup −3} range that corresponds to the growth of superfluid vortex instabilities due to mutual-friction action, and an adjacent, low wavenumber, k{sup −5/3} regime that emerges during the termination of this growth, as superfluid vortices agglomerate between intense normal-fluid vorticity regions, and weakly polarized bundles are formed. There is also evidence of a high wavenumber k{sup −1} range that corresponds to the probing of individual-vortex velocity fields. The Kelvin waves cascade (the main dynamical effect in zero temperature superfluids) appears to be damped at the intervortex space scale.

• OSTI ID: 22310807
• Journal Information: Physics of Fluids (1994), Journal Name: Physics of Fluids (1994) Journal Issue: 10 Vol. 26; ISSN 1070-6631; ISSN PHFLE6
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ENERGY SPECTRA
FRICTION
HELIUM II
INSTABILITY
NAVIER-STOKES EQUATIONS
REYNOLDS NUMBER
SUPERFLUIDITY
TURBULENCE
VELOCITY
VORTICES