Acoustic Resonances in Helium Fluids Excited by Quartz Tuning Forks

Salmela, Anssi; Tuoriniemi, Juha; Rysti, J.

doi:10.1007/s10909-010-0246-8

Cited by 30 publications

(35 citation statements)

References 10 publications

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“…It should be emphasized, however, that the temperature may be so low that there is present a negligible fraction of normal fluid, so the presence of normal fluid is not essential for the behavior we have described, the linear drag being then associated with the internal friction. It should also be added that, especially at high frequencies of oscillation, there can be a significant contribution to the damping from acoustic emission, but we shall not pursue this complication (10,(13)(14)(15).…”

Section: Superfluid Helium | Quantized Vortex Linesmentioning

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: Superfluid Helium | Quantized Vortex Linesmentioning

confidence: 99%

Quantum turbulence generated by oscillating structures

Vinen

Skrbek

2014

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

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“…In recent years they have been used in quantum fluids research to study many different properties such as viscosity [7,8], turbulence [9,10], cavitation [11], Andreev scattering [12,13], and acoustic modes [14,15].…”

Section: Introductionmentioning

confidence: 99%

Response of a Mechanical Oscillator in Solid 4He

et al. 2013

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We present the first measurements of the response of a mechanical oscillator in solid 4 He. We use a lithium niobate tuning fork operating in its fundamental resonance mode at a frequency of around 30 kHz. Measurements in solid 4 He were performed close to the melting pressure. The tuning fork resonance shows substantial frequency shifts on cooling from around 1.5 K to below 10 mK. The response shows an abrupt change at the bcc-hcp transition. At low temperatures, below around 100 mK, the resonance splits into several overlapping resonances.

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“…These kind of anomalies in the quartz tuning fork response, or second sound resonances, have been observed before [9][10][11], but the detailed mechanism producing the anomalies has not been thoroughly investigated. Calculations of the coupling factors between first and second sound in helium mixtures have been presented by Brusov et al [12], but, as first noted by Rysti [13], they made a sign error in their calculations, which washed out the decoupling behavior.…”

Section: Introductionmentioning

confidence: 94%

Decoupling of first sound from second sound in dilute He3–superfluidHe4 mixtures

2016

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Riekki, Tapio; Manninen, M. S.; Tuoriniemi, Juha Decoupling of first sound from second sound in dilute 3He-superfluid 4He mixtures Bulk superfluid helium supports two sound modes: first sound is an ordinary pressure wave, while second sound is a temperature wave, unique to superfluid systems. These sound modes do not usually exist independently, but rather variations in pressure are accompanied by variations in temperature, and vice versa. We studied the coupling between first and second sound in dilute 3 He -superfluid 4 He mixtures, between 1.6 and 2.2 K, at 3 He concentrations ranging from 0% to 11%, under saturated vapor pressure, using a quartz tuning fork oscillator. Second sound coupled to first sound can create anomalies in the resonance response of the fork, which disappear only at very specific temperatures and concentrations, where two terms governing the coupling cancel each other, and second sound and first sound become decoupled.

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Acoustic Resonances in Helium Fluids Excited by Quartz Tuning Forks

Cited by 30 publications

References 10 publications

Quantum turbulence generated by oscillating structures

Quantum turbulence generated by oscillating structures

Response of a Mechanical Oscillator in Solid 4He

Decoupling of first sound from second sound in dilute He3–superfluidHe4 mixtures

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