Dynamics of the density of quantized vortex lines in counterflow turbulence: Experimental investigation

Varga, E.; Skrbek, L.

doi:10.1103/physrevb.97.064507

Cited by 12 publications

(14 citation statements)

References 45 publications

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“…4(d) and tabulated in Table I. They are slightly less than those reported in existing simulations [28,29] and experiments [30], but the overall trend, a decrease with increasing temperature, is preserved. Geometric factors, i.e., the relatively large size of the experimental flow channel, may be partially responsible for the difference.…”

Section: Experimental Measurement Of Cmentioning

confidence: 62%

Characterizing vortex tangle properties in steady-state He II counterflow using particle tracking velocimetry

Mastracci

Guo

2019

Phys. Rev. Fluids

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Historically, there is little faith in particle tracking velocimetry (PTV) as a tool to make quantitative measurements of thermal counterflow in He II, since tracer particle motion is complicated by influences from the normal fluid, superfluid, and quantized vortex lines, or a combination thereof.Recently, we introduced a scheme for differentiating particles trapped on vortices (G1) from particles entrained by the normal fluid (G2). In this paper, we apply this scheme to demonstrate the utility of PTV for quantitative measurements of vortex dynamics in He II counterflow. We estimate ℓ, the mean vortex line spacing, using G2 velocity data, and c 2 , a parameter related to the mean curvature radius of vortices and energy dissipation in quantum turbulence, using G1 velocity data. We find that both estimations show good agreement with existing measurements that were obtained using traditional experimental methods. This is of particular consequence since these parameters likely vary in space, and PTV offers the advantage of spatial resolution. We also show a direct link between power-law tails in transverse particle velocity probability density functions (PDFs) and reconnection of vortex lines on which G1 particles are trapped.

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Section: Experimental Measurement Of Cmentioning

confidence: 62%

Characterizing vortex tangle properties in steady-state He II counterflow using particle tracking velocimetry

Mastracci

Guo

2019

Phys. Rev. Fluids

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“…For a short transition time, counterflow is still driven by the excess entropy contained in the channel; for details, see refs. 63 and 64 . The quantum peak quickly decays, displaying a decay of the

1

type.…”

Section: Quantum Turbulence In the Two-fluid Regimementioning

confidence: 99%

“…The dynamics of vortex tangles in thermal counterflow are not fully understood by any means. Their complexity can be illustrated by an experimental study of thermal counterflow in a channel when the turbulence was not allowed to settle to a statistical steady state ( 64 ). This was achieved by modulating by a square-wave

and a similarly varying counterflow velocity

.…”

Section: Quantum Turbulence In the Two-fluid Regimementioning

confidence: 99%

Phenomenology of quantum turbulence in superfluid helium

Skrbek

Schmoranzer

Midlik

et al. 2021

Proc. Natl. Acad. Sci. U.S.A.

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Quantum turbulence—the stochastic motion of quantum fluids such as 4He and 3He-B, which display pure superfluidity at zero temperature and two-fluid behavior at finite but low temperatures—has been a subject of intense experimental, theoretical, and numerical studies over the last half a century. Yet, there does not exist a satisfactory phenomenological framework that captures the rich variety of experimental observations, physical properties, and characteristic features, at the same level of detail as incompressible turbulence in conventional viscous fluids. Here we present such a phenomenology that captures in simple terms many known features and regimes of quantum turbulence, in both the limit of zero temperature and the temperature range of two-fluid behavior.

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“…Here we need to take into account that in the considered range = 4 × 10 −3 − 6 × 10 −3 cm, the fit becomes unreliable and the experimental points tend to scatter, see Fig.11 in Ref. 39 . The experimental values for T = 1.95K are expectedly lower than our results for T = 1.9K.…”

Section: F Large-scale Superfluid Motionmentioning

confidence: 99%

Dynamics of turbulent plugs in a superfluid He4 channel counterflow

Pomyalov

2020

Phys. Rev. B

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Quantum turbulence in superfluid He-4 in narrow channels often takes the form of moving localized vortex tangles. Such tangles, called turbulent plugs, also serve as building blocks of quantum turbulence in wider channels. We report on a numerical study of various aspects of the dynamics and structure of turbulent plugs in a wide range of governing parameters. The unrestricted growth of the tangle in a long channel provides a unique view on a natural tangle structure including superfluid motion at many scales. We argue that the edges of the plugs propagate as turbulent fronts, following the advection-diffusion-reaction dynamics. This analysis shows that the dynamics of the two edges of the tangle have distinctly different nature. We provide an analytic solution of the equation of motion for the fronts that define their shape, velocities and effective diffusivity, and analyze these parameters for various flow conditions. arXiv:2002.05002v2 [cond-mat.other]

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Dynamics of the density of quantized vortex lines in counterflow turbulence: Experimental investigation

Cited by 12 publications

References 45 publications

Characterizing vortex tangle properties in steady-state He II counterflow using particle tracking velocimetry

Characterizing vortex tangle properties in steady-state He II counterflow using particle tracking velocimetry

Phenomenology of quantum turbulence in superfluid helium

Dynamics of turbulent plugs in a superfluid He4 channel counterflow

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