Oscillating grids turbulence generator for turbulent transport studies

Eidelman, A.; Elperin, T.; Kapusta, A.; Kleeorin, N.; Krein, A.

doi:10.5194/npg-9-201-2002

Cited by 9 publications

(7 citation statements)

References 16 publications

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“…Lacking direct measurements of d, we could get guidance from the oscillating grid experiments in classical fluids, see, e.g., Ref. 27, where the following estimate for the integral scale is given:…”

Section: Summary and Discussionmentioning

confidence: 99%

Bottleneck crossover between classical and quantum superfluid turbulence

2007

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We consider superfluid turbulence near absolute zero of temperature generated by classical means, e.g. towed grid or rotation but not by counterflow. We argue that such turbulence consists of a polarized tangle of mutually interacting vortex filaments with quantized vorticity. For this system we predict and describe a bottleneck accumulation of the energy spectrum at the classical-quantum crossover scale ℓ. Demanding the same energy flux through scales, the value of the energy at the crossover scale should exceed the Kolmogorov-41 spectrum by a large factor ln 10/3 (ℓ/a0) (ℓ is the mean intervortex distance and a0 is the vortex core radius) for the classical and quantum spectra to be matched in value. One of the important consequences of the bottleneck is that it causes the mean vortex line density to be considerably higher that based on K41 alone, and this should be taken into account in (re)interpretation of new (and old) experiments as well as in further theoretical studies.

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Section: Summary and Discussionmentioning

confidence: 99%

Bottleneck crossover between classical and quantum superfluid turbulence

2007

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“…5 shows a typical set of reconstructed trajectories. An overall vertical trend of particles motion can be seen which suggest the existence of a mean drift velocity, see [5,14]. This is expected as particles are slightly denser than the carrier fluid, see Table V.…”

Section: Single Time Velocity Statisticsmentioning

confidence: 76%

“…4, the dependency on L is only to the power 1, while the dependency on σ u is cubic. We therefore expect that major impacts on the overall estimate of L will be associated to changes of σ u rather that eventual small deviations of L. [5,7,29,38,40]. Furthermore, the experimental area is located at z = 4.6 ± 0.6M distance from the grid, and is expected to scale as z −2 .…”

Section: A Energy Injection At Large Scalesmentioning

confidence: 99%

Multi-scale energy budget of inertially driven turbulence in normal and superfluid helium

Sy,

Diribarne,

Rousset

et al. 2020

Preprint

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In this paper we present a novel hydrodynamic experiment using liquid 4 He. The flow is forced inertially by a canonical oscillating grid using either its normal (He I) or superfluid (He II) phase, generating a statistically stationary turbulence. We characterise the turbulent properties of the flow using 2D Lagrangian Particle tracking on hollow glass micro-spheres. As expected for tracer particles, the Voronoï tessellation on particle positions does not show a significant departure from a random Poisson process neither in He I nor He II phase. Particles' positions are tracked with high temporal resolution, allowing to resolve velocity fluctuations at integral and inertial scales while properly assessing the noise contribution. Additionally, we differentiate the particles' positions (by convolution with Gaussian kernels) in order to access small scale quantities like acceleration. Using these measured quantities and the formalism of classical Homogeneous Isotropic Turbulence (HIT) to perform an energy budget across scales we extract the energy injection rate at the large scale, the energy flux cascading through inertial scales, down to small scales at which it is dissipated. We found that in such inertially driven turbulence, regardless of the normal or superfluid state of the fluid, estimates of energy at the different scales are compatible with each other and consistent with oscillating grid turbulence results reported for normal fluids in the literature. The largest discrepancy shows up at small scales where the signal to noise ratio is harder to control and where the 2D measurement is contaminated by the 3D nature of the flow. This motivates to focus future experimental projects towards small scales, low noise and 3D measurements.

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“…Cheng and Law (2001) explored the turbulence generated by an oscillating-grid using non-intrusive instrument like Digital Particle Image Velocimetry (DPIV) technique. Eidelman et al (2002) studied the fully developed turbulence generated from the grid oscillation in a tunnel. Sumer et al (2003) described the results of an experimental study on the influence of externally generated turbulence on the bed load transport in an open channel flow.…”

Section: Introductionmentioning

confidence: 99%

Externally generated turbulence by a vertically oscillating grid plate and its impact on sediment transport rate

Ojha

Mazumder

Carstensen

et al. 2019

Coastal Engineering Journal

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Oscillating grids turbulence generator for turbulent transport studies

Cited by 9 publications

References 16 publications

Bottleneck crossover between classical and quantum superfluid turbulence

Bottleneck crossover between classical and quantum superfluid turbulence

Multi-scale energy budget of inertially driven turbulence in normal and superfluid helium

Externally generated turbulence by a vertically oscillating grid plate and its impact on sediment transport rate

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