Bathtub vortex in superfluid 
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Inui, Sosuke; Nakagawa, Tomo; Tsubota, Makoto

doi:10.1103/physrevb.102.224511

Cited by 8 publications

(5 citation statements)

References 35 publications

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“…This would be consistent with the general property that vortex lines are preferentially perpendicular to the external flow. This picture is also in agreement with the numerical simulation by Inui et al [26], who solved the motion of the quantized vortex lines under the influence of the vertical normal fluid flow.…”

Section: Discussionsupporting

confidence: 91%

Vortex line density of superfluid suction vortex

et al. 2021

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Although a suction vortex is the one of the most common vortices appearing in our everyday life, its internal structure has not been fully understood yet. One of the few things that we understand is that the radius of the core results from the competition between the diffusion of the vorticity due to the kinematic viscosity and the transportation of the vorticity due to the inward flow. To understand the structure of the suction vortex, we investigated a suction vortex produced in liquid helium. In the normal fluid phase, liquid helium behaves as a viscous fluid. In contrast, in the superfluid phase, a quantum vortex line carries all the microscopic circulation, and the suction vortex can be understood as a complex of quantized vortex lines. We generated a superfluid suction vortex with a cryogenic turbine and measured its circulation with a pulsed first sound circulation meter, and also measured the vorticity by the second sound attenuation technique. The experimental results indicate that the quantized vortex lines accumulated in the narrow region around the axis of symmetry due to an inward flow, the core structure of which cannot be described by a simple bundle of fully polarized quantized vortex lines.

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Section: Discussionsupporting

confidence: 91%

Vortex line density of superfluid suction vortex

et al. 2021

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“…The parabolic shape of the free surface in the former regime is consistent with solid-body rotation, which corresponds to a compact, polarized cluster of singly quantized vortices (called solid core) that forms under the finite depression. The hollow core can instead absorb individual circulation quanta and behave like a multiply quantized object 37 . To minimize the rotational flow injected by the spinning propeller into the experimental zone, we devised a unique recirculation strategy based on a purpose-built flow conditioner (see Methods ) that promotes formation of a centrally confined vortex cluster instead of a sparse vortex lattice.…”

Section: Mainmentioning

confidence: 99%

Rotating curved spacetime signatures from a giant quantum vortex

Švančara,

Smaniotto,

Solidoro

et al. 2024

Nature

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Gravity simulators1 are laboratory systems in which small excitations such as sound2 or surface waves3,4 behave as fields propagating on a curved spacetime geometry. The analogy between gravity and fluids requires vanishing viscosity2–4, a feature naturally realized in superfluids such as liquid helium or cold atomic clouds5–8. Such systems have been successful in verifying key predictions of quantum field theory in curved spacetime7–11. In particular, quantum simulations of rotating curved spacetimes indicative of astrophysical black holes require the realization of an extensive vortex flow12 in superfluid systems. Here we demonstrate that, despite the inherent instability of multiply quantized vortices13,14, a stationary giant quantum vortex can be stabilized in superfluid 4He. Its compact core carries thousands of circulation quanta, prevailing over current limitations in other physical systems such as magnons5, atomic clouds6,7 and polaritons15,16. We introduce a minimally invasive way to characterize the vortex flow17,18 by exploiting the interaction of micrometre-scale waves on the superfluid interface with the background velocity field. Intricate wave–vortex interactions, including the detection of bound states and distinctive analogue black hole ringdown signatures, have been observed. These results open new avenues to explore quantum-to-classical vortex transitions and use superfluid helium as a finite-temperature quantum field theory simulator for rotating curved spacetimes19.

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“…The main reasons for this is the lack of a technique to directly measure the vorticity. Our ultimate goal is to understand the structure of the suction vortex using superfluid helium, because all the circulating flow in the superfluid helium can be characterized by the configuration and the motion of the quantized vortex lines [6], and the vortex line density can be measured by the second sound attenuation technique [7,8]. In this paper, we report a new experimental procedure to obtain the macroscopic circulation of the superfluid suction vortex using an ultrasound circulation meter (USCM) system with an update of the acquisition technique we reported in Ref.…”

Section: Introductionmentioning

confidence: 99%

Circulation of Superfluid Suction Vortex

et al. 2022

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Although the suction vortex is the one of the most common vortices, its flow structure has not been fully understood. The main reasons for this are the experimental difficulty due to the very rapid flow change near the core. However, superfluid helium may help us better understand the suction vortex, because the flow in the superfluid helium can be characterized by the circulation measured by the first sound velocity, and the configuration of the quantized vortex lines can be measured with the second sound attenuation technique, as reported in our previous results [Phys. Rev. Fluids, 6, 064802 (2021)]. In this paper, we report the effectiveness of an ultrasound circulation meter using the correlation-based differential time-of-flight method. Using this technique, the accuracy for measuring the circulation was greatly improved; we found that the circulation was proportional to the rotation speed of the turbine, which can be interpreted by considering the transport and dissipation of total angular momentum in the fluid.

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Bathtub vortex in superfluid He4

Cited by 8 publications

References 35 publications

Vortex line density of superfluid suction vortex

Vortex line density of superfluid suction vortex

Rotating curved spacetime signatures from a giant quantum vortex

Circulation of Superfluid Suction Vortex

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