Intermittency enhancement in quantum turbulence

Abstract

Intermittency is a hallmark of turbulence, which exists not only in turbulent flows of classical viscous fluids but also in flows of quantum fluids such as superfluid ${}^4$He. Despite the established similarity between turbulence in classical fluids and quasi-classical turbulence in superfluid ${}^4$He, it has been predicted that intermittency in superfluid ${}^4$He is temperature dependent and enhanced for certain temperatures, which strikingly contrasts the nearly flow-independent intermittency in classical turbulence. Experimental verification of this theoretical prediction is challenging since it requires well-controlled generation of quantum turbulence in ${}^4$He and flow measurement tools with high spatial and temporal resolution. Here, we report an experimental study of quantum turbulence generated by towing a grid through a stationary sample of superfluid ${}^4$He. The decaying turbulent quantum flow is probed by combining a recently developed He${}_2^{\ast }$ molecular tracer-line tagging velocimetry technique and a traditional second sound attenuation method. We observe quasi-classical decays of turbulent kinetic energy in the normal fluid and of vortex line density in the superfluid component. For several time instants during the decay, we calculate the transverse velocity structure functions. Their scaling exponents, deduced using the extended self-similarity hypothesis, display non-monotonic temperature-dependent intermittency enhancement, in excellent agreement with recent theoretical/numerical study of Biferale et al. [Phys. Rev. Fluids 3, 024605 (2018)].

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Cited by in corpus (11)

• Rotating Curved Spacetime Signatures from a Giant Quantum Vortex
• Intermittency of velocity circulation in quantum turbulence
• ${}^4$He Counterflow Differs Strongly from Classical Flows: Anisotropy on Small Scales
• Statistics of turbulence and intermittency enhancement in superfluid ${}^4$He counterflow
• Quench spot detection for superconducting accelerator cavities via flow visualization in superfluid helium-4
• Eulerian and Lagrangian second-order statistics of superfluid ${}^4$He grid turbulence
• A cryogenic-helium pipe flow facility with unique double-line molecular tagging velocimetry capability
• Inviscid diffusion of vorticity in low temperature superfluid helium
• The Statistical Properties of Superfluid Turbulence in ${}^4$He from the Hall-Vinen-Bekharevich-Khalatnikov Model
• Disentangling temperature and Reynolds number effects in quantum turbulence
• Theory of anisotropic superfluid He-4 counterflow turbulence