Transition from laminar to turbulent drag in flow due to a vibrating quartz fork

Blažková, Michaela; Schmoranzer, David; Skrbek, L.

doi:10.1103/physreve.75.025302

Cited by 60 publications

(43 citation statements)

References 11 publications

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“…30, chapter 5). We note also the critical velocity for the formation of a classical turbulent wake behind an oscillating structure: in the case when the viscous penetration depth is greater than the size of the structure (low frequency), the critical velocity is given by putting the Reynolds number equal to unity; in the opposite limit, it is given in order of magnitude by (31,32):…”

Section: The Development Of Quantum Turbulencementioning

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: The Development Of Quantum Turbulencementioning

confidence: 99%

Quantum turbulence generated by oscillating structures

Vinen

Skrbek

2014

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

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“…Additional experiments in water at room temperature (dynamically similar to the ones in normal helium) using the Baker visualization technique [25] and Kalliroscope [26] have proved that the observed change in the drag force is indeed associated with turbulence [27]. In the normal helium liquid and helium gas, which both behave as classical fluids of low kinematic viscosity, the obtained critical velocities conform to the expected scaling law of v c ∝ √ νω, see [28,29]. When the same data are plotted in terms of the drag coefficient, an unexpected feature is seen for the data taken in the superfluid, esp.…”

Section: Efm11mentioning

confidence: 89%

Applications of the quartz tuning fork in classical and superfluid hydrodynamics

Schmoranzer

Mantia

Skrbek

2012

EPJ Web of Conferences

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“…6, where the calibration procedure and the potential of the fork used as thermometer or pressure gauge has been considered in detail. Moreover, if driven in the nonlinear flow regime, it serves as an excellent tool to study the crossover from the laminar drag regime (characterized by a linear drive versus velocity dependence) to the turbulent drag regime (characterized by a quadratic drive versus velocity dependence) in both classical viscous fluids [7] and quantum fluids [8].…”

Section: Introductionmentioning

confidence: 99%

On cavitation in liquid helium in a flow due to a vibrating quartz fork

Blažková

Schmoranzer

Skrbek

2008

Low Temperature Physics

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Cavitation in normal and superfluid liquid 4 He at saturated vapor pressure and slightly elevated pressures has been experimentally studied in a flow due to quartz forks vibrating at high amplitudes. Above the temperature-and pressure-dependent critical velocity, heterogeneous cavitation is observed both visually and electrically, as a breakdown of the resonance response of the fork. We compare our results with available experimental and discuss them using existing theoretical models. In particular, we show that thermal effects leading to local overheating of the vicinity of the fork have to be taken into account, especially in normal liquid 4 He.PACS: 47.55.dp Drop and bubble formation.

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Transition from laminar to turbulent drag in flow due to a vibrating quartz fork

Cited by 60 publications

References 11 publications

Quantum turbulence generated by oscillating structures

Quantum turbulence generated by oscillating structures

Applications of the quartz tuning fork in classical and superfluid hydrodynamics

On cavitation in liquid helium in a flow due to a vibrating quartz fork

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