The Approach to Vortex Reconnection

Tebbs, Richard; Youd, Anthony J.; Barenghi, Carlo F.

doi:10.1007/s10909-010-0287-z

Cited by 43 publications

(30 citation statements)

References 17 publications

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“…Many authors have focused on the possibility that there is a universal route to reconnection, which may take the form of a vortex ring cascade [42,43], a particular rule for the cusp angles [44,45], or, more promising, a special scaling with time of the minimum distance δ(t) between the reconnecting vortex strands. It is on the last property that we concentrate our attention.…”

Section: Is There a Universal Route To Reconnection ?mentioning

confidence: 99%

Crossover from interaction to driven regimes in quantum vortex reconnections

Galantucci

Baggaley

Parker

et al. 2019

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

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Reconnections of coherent filamentary structures play a key role in the dynamics of fluids, redistributing energy and helicity among the length scales, triggering dissipative effects and inducing fine-scale mixing. Unlike ordinary (classical) fluids where vorticity is a continuous field, in superfluid helium and in atomic Bose-Einstein condensates (BECs) vorticity takes the form of isolated quantised vortex lines, which are conceptually easier to study. New experimental techniques now allow visualisation of individual vortex reconnections in helium and condensates. It has long being suspected that reconnections obey universal laws, particularly a universal scaling with time of the minimum distance between vortices δ. Here we perform a comprehensive analysis of this scaling across a range of scenarios relevant to superfluid helium and trapped condensates, combining our own numerical simulations with the previous results in the literature. We reveal that the scaling exhibit two distinct fundamental regimes: a δ ∼ t 1/2 scaling arising from the mutual interaction of the reconnecting strands and a δ ∼ t scaling when extrinsic factors drive the individual vortices. RECONNECTIONS IN CLASSICAL AND QUANTUM SYSTEMSarXiv:1812.00473v2 [cond-mat.quant-gas]

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Section: Is There a Universal Route To Reconnection ?mentioning

confidence: 99%

Crossover from interaction to driven regimes in quantum vortex reconnections

Galantucci

Baggaley

Parker

et al. 2019

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

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“…We know from experiments [34] and from more microscopic models [35][36][37][38] that superfluid vortex lines can reconnect with each other when they come sufficiently close, as envisaged by Feynman [39]. Superfluid vortex reconnections do not violate Kelvin's theorem as near the axis of the vortex core, where density and pressure vanish and velocity diverges, the governing Gross-Pitaevski equation (GPE) differs from the classical Euler equation.…”

Section: Introductionmentioning

confidence: 99%

The Sensitivity of the Vortex Filament Method to Different Reconnection Models

Baggaley

2012

J Low Temp Phys

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We present a detailed analysis on the effect of using different algorithms to model the reconnection of vortices in quantum turbulence, using the thin-filament approach. We examine differences between four main algorithms for the case of turbulence driven by a counterflow. In calculating the velocity field we use both the local induction approximation (LIA) and the full Biot-Savart integral. We show that results of Biot-Savart simulations are not sensitive to the particular reconnection method used, but LIA results are.

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“…At high vortex densities, vortex reconnection events, which are believed to be responsible for the large-scale behavior of quantum turbulence [2][3][4][5], become increasingly important. Quantum turbulence is associated with the proliferation of quantized vortices [6,7].…”

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confidence: 99%

Onset of nanoscale dissipation in superfluid He4 at zero temperature: Role of vortex shedding and cavitation

et al. 2017

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Two-dimensional flow past an infinitely long cylinder of nanoscopic radius in superfluid 4 He at zero temperature is studied by time-dependent density functional theory. The calculations reveal two distinct critical phenomena for the onset of dissipation: 1) vortex-antivortex pair shedding from the periphery of the moving cylinder and 2) appearance of cavitation in the wake, which possesses similar geometry as observed experimentally for fast moving micrometer-scale particles in superfluid 4 He. Vortex pairs with the same circulation are occasionally emitted in the form of dimers, which constitute the building blocks for the Benard-von Karman vortex street structure observed in classical turbulent fluids and Bose-Einstein condensates (BEC). The cavitation induced dissipation mechanism should be common to all superfluids that are self-bound and have a finite surface tension, which include the recently discovered self-bound droplets in ultracold Bose gases.PACS numbers: 67.25.dg,67.25.dk, 67.85.-d One of the manifestations of 4 He superfluidity at zero temperature (T ) is the frictionless liquid flow through capillaries at sufficiently low velocities. Based on the well-known Landau criterion, the onset of dissipation is related to the unusual form of the superfluid dispersion relation, ǫ(p), which exhibits roton minimum ǫ(p min ) at p min . The flow should become dissipative when the velocity reaches the critical Landau value v L = ǫ(p min )/p min = 59 m/s [1]. Similarly, an object moving in superfluid 4 He should experience drag only above a certain critical velocity threshold v c . It is well established experimentally that objects moving already at much lower velocities than v L experience drag due to the emission of non-linear excitations in the form of quantized vortices; see for example Ref. [1].Multiple interacting vortices in a superfluid can form a well-defined lattice or a more complicated vortex tangle, depending on their geometry and circulation. At high vortex densities, vortex reconnection events, which are believed to be responsible for the large-scale behavior of quantum turbulence [2-5], become increasingly important. Quantum turbulence is associated with the proliferation of quantized vortices [6,7]. From the experimental point of view, vorticity can be created by stirring or rotating the superfluid [8][9][10].Although quantized vorticity plays a key role in the onset of dissipation in superfluid flows, a fundamental understanding of their role in exerting drag on moving objects and the dependence of the associated critical velocity on the object size is still lacking. In this paper, we identify a new, previously overlooked, energy dissipation mechanism that takes place also well below v L . The energy loss and the induced drag force on the object in this mechanism originate from the formation of cavitation bubbles in the wake. Cavitation bubbles play a crucial role in the appearance of drag as they may act as vortex nucleation seeds through local distortions of their surface and, more importa...

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The Approach to Vortex Reconnection

Cited by 43 publications

References 17 publications

Crossover from interaction to driven regimes in quantum vortex reconnections

Crossover from interaction to driven regimes in quantum vortex reconnections

The Sensitivity of the Vortex Filament Method to Different Reconnection Models

Onset of nanoscale dissipation in superfluid He4 at zero temperature: Role of vortex shedding and cavitation

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