Time-of-Flight Experiments of Vortex Rings Propagating from Turbulent Region of Superfluid 4He at High Temperature

Nago, Yusuke; Ogawa, T.; Obara, K.; Yano, H.; Ishikawa, Osamu; Hata, Tōju

doi:10.1007/s10909-010-0277-1

Cited by 14 publications

(4 citation statements)

References 14 publications

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“…More precisely, if wire W A is first driven at a high velocity, and then wire W B is driven above its critical velocity, the response of wire W A suddenly falls by a large factor, indicating the generation of turbulence by wire W A . The excitation of a wire, such as W B , on which there is a remanent vortex leads to the emission of a beam of vortex rings (22), and the generation of turbulence around wire W A must have been nucleated by the attachment of one or more of these rings to this wire.…”

Section: −1mentioning

confidence: 99%

Quantum turbulence generated by oscillating structures

Vinen

Skrbek

2014

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

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The paper summarizes important aspects of quantum turbulence that have been studied successfully with oscillating structures. It describes why some aspects are proving hard to interpret, and it outlines the need for new types of experiment and new developments in theoretical and computational work. superfluid helium | quantized vortex linesThis paper is concerned with the generation of quantum turbulence (1-3) in liquid helium by various forms of oscillating structure, such as a cylinder oscillating in a direction normal to its length. Many experiments on the generation of quantum turbulence by such structures have been reported, involving not only cylinders (or wires), but also spheres, tuning forks, and grids. Many of these experiments and their possible interpretation have already been reviewed (4). We are not aiming to produce another conventional review, and we shall not consider all that has been achieved. Instead, our aim is to focus on three particular aspects of this type of work: first, on experiments that have already contributed significantly to our understanding of issues that are, as we see them, of general and fundamental importance; second, on an exposure of the difficulties in interpreting many of the experiments in any real detail, in the way that has been achieved in analogous work on classical fluids; and third, on ways in which we might overcome these difficulties, which are both theoretical and experimental. We shall be concerned ultimately with both superfluid He. There are of course connections between quantum turbulence produced by oscillating structures and more general aspects of such turbulence. The role of remanent vorticity in the nucleation and stability of quantum turbulence is universally important, and, as we discuss in a later section, it is here that experiments with oscillating structures have been particularly instructive. At a more subtle level, there is the question of the extent to which quantum turbulence is similar to classical turbulence. The observation of a Kolmogorov energy spectrum on large length scales (larger than the vortex-line spacing) in homogeneous quantum turbulence is often quoted as evidence for this similarity. As we shall see, some aspects of the quantum turbulence produced by oscillating structures provide additional evidence. However, in contrast to homogeneous turbulence, quantum turbulence produced by an oscillating structure must be strongly influenced by the boundary conditions at a solid wall. As we discuss in a section devoted to the development of quantum turbulence, uncertainty about the boundary conditions relevant to quantum turbulence hinders interpretation of the experiments and calls for renewed experimental and theoretical study.Almost all of the experiments have involved measurements of the fluid dynamical force on the structure as a function of the amplitude of the oscillations. This force can be divided into a drag, which is in phase with the velocity and therefore dissipative, and a force that is in quadrature with the velocity and ...

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Section: −1mentioning

confidence: 99%

Quantum turbulence generated by oscillating structures

Vinen

Skrbek

2014

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

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“…Until now, all other oscillators measured in superfluid 4 He begin to generate their own turbulence immediately after being exposed to vorticity in the fluid. While this has enabled many rich experiments [33][34][35][36][37]95], it precludes the use of these devices to continuously sense quantum turbulence.…”

Section: Discussionmentioning

confidence: 99%

Damping of a micro-electromechanical oscillator in turbulent superfluid $^4$He: A novel probe of quantized vorticity in the ultra-low temperature regime

Barquist,

Jiang,

Gunther

et al. 2020

Preprint

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We report a comprehensive investigation of the effects of quantum turbulence and quantized vorticity in superfluid 4 He on the motion of a micro-electromechanical systems (MEMS) resonator. We find that the MEMS is uniquely sensitive to quantum turbulence present in the fluid. To generate turbulence in the fluid, a quartz tuning fork (TF) is placed in proximity to the MEMS and driven at large amplitude. We observe that at low velocity, the MEMS is damped by the turbulence, and that above a critical velocity, vc 5 mm s −1 , the turbulent damping is greatly reduced. We find that above vc, the damping of the MEMS is reduced further for increasing velocity, indicating a velocity dependent coupling between the surface of the MEMS and the quantized vortices constituting the turbulence. We propose a model of the interaction between vortices in the fluid and the surface of the MEMS. The sensitivity of these devices to a small number of vortices and the almost unlimited customization of MEMS open the door to a more complete understanding of the interaction between quantized vortices and oscillating structures, which in turn provides a new route for the investigation of the dynamics of single vortices.

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“…One of the main challenges for the experimentalist is then to come up with fast micro-sensors suited to helium flows. Over the last two decades, there has been various developments of local cryogenic probes, specifically hot wires [2,6,7], micro-thermometers [8,9], second-sound tweezers [10], Pitot-tube-like anemometers [11,12], vibrating wires [13,14] and quartz tuning forks [15,16].…”

Section: Introductionmentioning

confidence: 99%

Cantilever anemometer based on a superconducting micro-resonator: Application to superfluid turbulence

Salort

Monfardini

Roche

2012

Review of Scientific Instruments

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We present a new type of cryogenic local velocity probe that operates in liquid helium (1 K < T < 4.2 K) and achieves a spatial resolution of ≈ 0.1 mm. The operating principle is based on the deflection of a micro-machined silicon cantilever which reflects the local fluid velocity. Deflection is probed using a superconducting niobium micro-resonator sputtered on the sensor and used as a strain gauge. We present the working principle and the design of the probe, as well as calibration measurements and velocity spectra obtained in a turbulent helium flow above and below the superfluid transition.

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Time-of-Flight Experiments of Vortex Rings Propagating from Turbulent Region of Superfluid 4He at High Temperature

Cited by 14 publications

References 14 publications

Quantum turbulence generated by oscillating structures

Quantum turbulence generated by oscillating structures

Damping of a micro-electromechanical oscillator in turbulent superfluid $^4$He: A novel probe of quantized vorticity in the ultra-low temperature regime

Cantilever anemometer based on a superconducting micro-resonator: Application to superfluid turbulence

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