Cross-linking of two vortex rings

Oshima, Yuko; Izutsu, Naoki

doi:10.1063/1.866593

Cited by 36 publications

(12 citation statements)

References 4 publications

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“…[1][2][3][4] Acoustic sound generated by a collision of vortex rings is also a fundamental problem in vortex sound. A lot of studies have been done for head on as well as oblique collisions both experimentally [5][6][7][8] and computationally.…”

Section: Introductionmentioning

confidence: 99%

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Sound generation by head-on and oblique collisions of two vortex rings

Nakashima¹

2008

Physics of Fluids

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Sound generation by head-on and oblique collisions of two vortex rings with equal strength is investigated by a direct numerical simulation. The three-dimensional, unsteady, compressible Navier-Stokes equations are solved by a finite difference method, not only for a near-vortical field but also for a far-acoustic field. The theory of vortex sound is also applied to investigate the detailed relation between the vortex ring motion and the acoustic wave mode. Generation of two sound pressure waves, which are called the first and second pulses, is observed in the numerical results. The theoretical results show that, for the head-on collision, the generations of the first and second pulses are due to the variations of vorticity moment, associated with a decrease in the translational velocity of the vortex ring near the collision plane and its stretching motion, respectively. On the other hand, for the oblique collision, in addition to such generation mechanisms, the reconnection of vortex lines also affects the generation of the second pulse. The reconnection of vortex lines occurs more rapidly for a smaller collision angle, and therefore its contribution to the second pulse becomes large. In fact, in the oblique collision at a right angle, the generation of the second pulse is closely related to the reconnection of vortex lines, which can be seen by analyzing both the near and far fields. Furthermore, for a smaller collision angle, the reconnection of vortex lines leads to more rapid variation of the vorticity, which enhances asymmetric features of the second pulse exhibited by the octupole mode ͑third-order wave mode͒.

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Section: Introductionmentioning

confidence: 99%

“…[2][3][4] The vortex reconnection is considered to be an important process in viscous vortical and turbulent flows. Kida et al 4 carried out numerical simulations of the oblique collision for several initial angles.…”

Section: Introductionmentioning

confidence: 99%

Sound generation by head-on and oblique collisions of two vortex rings

Nakashima¹

2008

Physics of Fluids

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“…He examined the decrease of circulation for each vortex core during the interaction of vortex rings, and discussed the correlation between the circulation decrease and the viscosity effect. Downloaded by ["Queen's University Libraries, Kingston"] at 17:05 03 February 2015 Izutsu et al (1988) developed an automatic measurement system for the timedependent velocity field of the vortex rings interaction by the use of a hot wires anemometer. They conducted a quantitative measurement for the velocity field of vortex rings generation and interaction for a Reynolds number of 2500.…”

Section: Introductionmentioning

confidence: 99%

Numerical Study on Cut-and-Connect of Two Vortex Rings Along Parallel Axes

Chen¹,

Hinada

Oshima

1994

International Journal of Computational Fluid Dynamics

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A numerical study has been conducted to investigate the interaction of two viscous vortex rings along parallel axes. The generation of two vortex rings created by the ejection of a fluid through orifices and their cut-and-connect process were numerically simulated by solving the three-dimensional and timedependent Navier-Stokes equations. Based on the quantitative velocity and pressure data obtained from the Navier-Stokes simulation, the distribution and the evolution of the vorticity, helicity density and energy dissipation function were analyzed. The helicity density and its relation with the energy dissipation function in three-dimensional flow fields were also examined. 11 was found that the energy dissipation plays an important role in the cancellation of the vortex circulation during the vortex tubes cutting. This energy dissipation process may be used to explain the cut-and-connect of vortex tubes in the high Reynolds number turbulent flow. The numerical solutions were compared with the experimental observations and measurements under the similar condition. The correspondence between the numerical simulation and the experimental measurement was satisfactory.

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“…Their presence in the cardiac tissues is many times the cause of arrhythmias and tachycardias, which finally lead to heart failure [6,7]. So the interaction of scroll waves may have far-reaching consequences on cardiac activity.In fluids and liquid crystals, there is evidence of vortex interaction leading to interesting phenomena like filament reconnection [8][9][10]. If likewise, scroll rings interact and reconnect, then small rings may merge and form large ones that will have enhanced lifetimes.…”

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confidence: 97%

Interaction of scroll waves in an excitable medium: Reconnection and repulsion

Das

Dutta

2015

Phys. Rev. E

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Scroll waves of reentrant activity and their interactions pose a serious threat to cardiac health. In experiments with the Belousov-Zhabotinsky reaction we demonstrate the interaction of scroll waves. We show that depending on their mutual orientation, two scroll rings can push each other away and rupture on touching the system boundary, or they can reconnect to form a single, large ring. Reconnection only occurs when the filaments lie within one core length of each other. The reconnected filament has extended lifetimes, which could have serious implications in systems where they occur. The experimental results are explained on the basis of a simple numerical model.

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Cross-linking of two vortex rings

Cited by 36 publications

References 4 publications

Sound generation by head-on and oblique collisions of two vortex rings

Sound generation by head-on and oblique collisions of two vortex rings

Numerical Study on Cut-and-Connect of Two Vortex Rings Along Parallel Axes

Interaction of scroll waves in an excitable medium: Reconnection and repulsion

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