scholarly journals Inverse centrifugal effect induced by collective motion of vortices in rotating turbulent convection

2020 ◽  
Author(s):  
Shan-Shan Ding ◽  
Kai Leong Chong ◽  
Jun-Qiang Shi ◽  
Guang-Yu Ding ◽  
Hao-Yuan Lu ◽  
...  
Keyword(s):  
Collective Motion ◽  
Fluid Motion ◽  
Vortex Motion ◽  
Turbulent Convection ◽  
Fluid System ◽  
Centrifugal Effect ◽  
Scale Free ◽  
Range Correlation ◽  
Outward Motion ◽  
Cluster Length

Abstract When a fluid system is subject to strong rotation, centrifugal fluid motion is expected, i.e., denser (lighter) fluid moves outward (inward) from (toward) the axis of rotation. Here we demonstrate, both experimentally and numerically, the existence of an unexpected outward motion of warm and lighter vortices in rotating turbulent convection. This anomalous vortex motion occurs under rapid rotations when the centrifugal buoyancy is sufficiently strong to induce a symmetry-breaking in the vorticity field, i.e., the vorticity of the cold anticyclones overrides that of the warm cyclones. We show that through hydrodynamic interactions the densely populated vortices can self-aggregate into coherent clusters and exhibit collective motion in this flow regime. Interestingly, the correlation of the vortex velocity fluctuations within a cluster is scale-free, with the correlation length being about 30% of the cluster length. Such long-range correlation leads to the collective outward motion of cyclones. Our study provides new understanding of vortex dynamics that are widely present in nature.

scholarly journals Inverse centrifugal effect induced by collective motion of vortices in rotating thermal convection

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Shan-Shan Ding ◽  
Kai Leong Chong ◽  
Jun-Qiang Shi ◽  
Guang-Yu Ding ◽  
Hao-Yuan Lu ◽  
...  
Keyword(s):  
Thermal Convection ◽  
Collective Motion ◽  
Fluid Motion ◽  
Vortex Motion ◽  
Fluid System ◽  
Centrifugal Effect ◽  
Scale Free ◽  
Range Correlation ◽  
Outward Motion ◽  
Cluster Length

AbstractWhen a fluid system is subject to strong rotation, centrifugal fluid motion is expected, i.e., denser (lighter) fluid moves outward (inward) from (toward) the axis of rotation. Here we demonstrate, both experimentally and numerically, the existence of an unexpected outward motion of warm and lighter vortices in rotating thermal convection. This anomalous vortex motion occurs under rapid rotations when the centrifugal buoyancy is sufficiently strong to induce a symmetry-breaking in the vorticity field, i.e., the vorticity of the cold anticyclones overrides that of the warm cyclones. We show that through hydrodynamic interactions the densely distributed vortices can self-aggregate into coherent clusters and exhibit collective motion in this flow regime. Interestingly, the correlation of the vortex velocity fluctuations within a cluster is scale-free, with the correlation length being proportional ( ≈ 30%) to the cluster length. Such long-range correlation leads to the counterintuitive collective outward motion of warm vortices. Our study brings insights into the vortex dynamics that are widely present in nature.

scholarly journals A possible quantum fluid-dynamical approach to vortex motion in nuclei

2017 ◽  
Vol 26 (04) ◽  
pp. 1750020
Author(s):  
Seiya Nishiyama ◽  
João da Providência
Keyword(s):  
Fluid Dynamics ◽  
Rotational Motion ◽  
Collective Motion ◽  
Rotational Velocity ◽  
Fluid Motion ◽  
Vortex Motion ◽  
Representation Formula ◽  
Essential Point ◽  
Quantum Fluid ◽  
Long Time

The essential point of Bohr–Mottelson theory is to assume an irrotational flow. As was already suggested by Marumori and Watanabe, the internal rotational motion, i.e., the vortex motion, however, may exist also in nuclei. So, we must take the vortex motion into consideration. In classical fluid dynamics, there are various ways to treat the internal rotational velocity. The Clebsch representation, [Formula: see text] is very powerful and allows for the derivation of the equations of fluid motion from a Lagrangian. Making the best use of this advantage, Kronig–Thellung, Ziman and Ito obtained a Hamiltonian including the internal rotational motion, the vortex motion, through the term [Formula: see text]. Going to quantum fluid dynamics, Ziman and Thellung finally derived the roton spectrum of liquid Helium II postulated by Landau. Is it possible to follow a similar procedure in the description of the collective vortex motion in nuclei? The description of such a collective motion has not been considered in the context of the Bohr–Mottelson model (BMM) for a long time. In this paper, we will investigate the possibility of describing the vortex motion in nuclei on the basis of the theories of Ziman and Ito together with Marumori’s work.

4D Investigation of Vortex Fluid Motion Inside the Eyeball

2021 ◽  
pp. 73-88
Author(s):  
S.A. Skladchikov ◽  
N.P. Savenkova ◽  
P.I. Vysikaylo ◽  
S.E. Avetisov ◽  
D.V. Lipatov ◽  
...  
Keyword(s):  
Numerical Models ◽  
Fluid Motion ◽  
Vortex Motion ◽  
Dissipative System ◽  
Fluid Flows ◽  
Vitreous Cavity ◽  
Posterior Chamber ◽  
Medicinal Substance ◽  
Fluid Transfer ◽  
And Diffusion

The eye is a complex system of boundaries and fluids with different viscosities within the boundaries. At present, there are no experimental possibilities to thoroughly observe the dynamic 4D processes after one or another method of eye treatment is applied. The complexity of cumulative, i.e., focusing, and dissipative, i.e., scattering, convective and diffusion 4D fluxes of fluids in the eye requires 4D analytical and numerical models of fluid transfer in the human eyeball to be developed. The purpose of the study was to develop and then verify a numerical model of 4D cumulative-dissipative processes of fluid transfer in the eyeball. The study was the first to numerically evaluate the values of the characteristic time of the drug substance in the vitreous cavity until it is completely washed out, depending on the injection site; to visualize the paths of the vortex motion of the drug in the vitreous cavity; to determine the main parameters of the 4D fluid flows of the medicinal substance in the vitreous cavity, depending on the presence or absence of vitreous detachment from the wall of the posterior chamber of the eye. The results obtained are verified by the experimental data available to doctors. In the eye, as a partially open cumulative-dissipative system, Euler regions with high rates of cumulative flows and regions with low speeds or stagnant Lagrange flow zones are defined

The Research on the Theory of Plasmoid Shortens the Valid Insulation Distance by which Leads to the Breakdown & the Mathematical Models Based on it

2012 ◽  
Vol 433-440 ◽  
pp. 81-85
Author(s):  
Shun Yuan ◽  
Da Wei Hu
Keyword(s):  
Magnetic Field ◽  
Mathematical Model ◽  
Mathematical Models ◽  
High Voltage ◽  
Fluid Motion ◽  
The Self ◽  
Fluid System ◽  
Unknown Reason ◽  
Motion Features ◽  
Head Line

Scholars, in order to find out the reason of the unknown reason flashover of insulators for high voltage over-head line, have made a lot of research on it. There have been two theories put forward, both of which infer the impetus after appearance of the partial arc, neither of them expound how is the partial arc formed. Based on the two theories, this paper puts forward a new theory - the theory of plasmoid shortens the valid insulation distance by which leads to the breakdown, of whose main viewpoint is whether the breakdown occurs depends on the comparation between the valid insulation distance on insulator’s surface and the shortened valid insulation distance on insulator’s space around by the plasmoid. Furthermore, we put forward the plasmoid mathematical model by kinetics equations of fluid system. Particularly, except for the fluid motion features, the influence by the self-generating electric field and magnetic field must be considered

Natural Surface Oscillations of Rotating Fluid Along Radial Baffles of Rotor

2016 ◽  
Vol 138 (6) ◽  
Author(s):  
A. Nikiforov
Keyword(s):  
Dynamic Equilibrium ◽  
Fluid Motion ◽  
Plane Motion ◽  
Rotating Fluid ◽  
Cylindrical Chamber ◽  
Centrifugal Effect ◽  
Unperturbed Motion ◽  
Resonant Frequencies ◽  
Axial Coordinate ◽  
Lateral Deflections

This paper determines natural and resonant frequencies of radial–circular oscillations (waves) on the nonviscous, incompressible fluid partially and evenly filling similar compartments in a rotor that has the cylindrical chamber, solid radial baffles, and constant angular velocity. It is assumed as follows: influence of the gravity and surface tension is negligibly small as compared to the centrifugal effect; configuration of dynamic equilibrium (unperturbed motion) of fluid is an annular rigid body rotation; and the fluid motion perturbed by small lateral deflections of the rotor does not depend on the axial coordinate (plane motion).

scholarly journals On the existence of an exact solution of the Navier-Stokes equation pertaining to certain vortex motion

1972 ◽  
Vol 13 (4) ◽  
pp. 456-460
Author(s):  
K. Kuen Tam
Keyword(s):  
Exact Solution ◽  
Incompressible Fluid ◽  
Stokes Equation ◽  
Viscous Incompressible Fluid ◽  
Fluid Motion ◽  
Vortex Motion ◽  
Polar Coordinates ◽  
Navier Stokes ◽  
Navier Stokes Equation ◽  
Cylindrical Polar Coordinates

In 1942, Burgers [1] observed that in cylindrical polar coordinates, the steady Navier-Stokes equation governing viscous incompressible fluid motion can be reduced to a set of ordinary differential equations if the velocity components vr, vo and vz are assumed to have a special form.

DYNAMICS OF REACTION-DIFFUSION INTERFACES UNDER STOCHASTIC CONVECTION: PRELIMINARY RESULTS

1994 ◽  
Vol 04 (05) ◽  
pp. 1329-1331 ◽  
Author(s):  
A. CARETA ◽  
F. SAGUÉS ◽  
J.M. SANCHO
Keyword(s):  
Differential Equations ◽  
Propagation Velocity ◽  
Fluid Motion ◽  
Chemical Species ◽  
Reaction Diffusion ◽  
Turbulent Convection ◽  
Correlated Noise ◽  
Preliminary Results ◽  
Diffusion And Convection ◽  
Chemically Reacting

Some preliminary results to illustrate the effect of turbulent convection on the dynamics of physicochemical systems incorporating reaction, diffusion and convection of chemical species are given. The whole approach rests on the use of stochastic differential equations with spatiotemporal correlated noise. In particular, it is shown how the propagation velocity of a chemically reacting front can be enhanced due to the fluid motion.

Scale-free architectures support representational diversity

2020 ◽  
Vol 43 ◽  
Author(s):  
Chris Fields ◽  
James F. Glazebrook
Keyword(s):  
Cognitive Architecture ◽  
Levels Of Abstraction ◽  
Scale Free ◽  
Abstract Representations ◽  
Computational Architecture ◽  
Architectural Models ◽  
Cognition Scale

Abstract Gilead et al. propose an ontology of abstract representations based on folk-psychological conceptions of cognitive architecture. There is, however, no evidence that the experience of cognition reveals the architecture of cognition. Scale-free architectural models propose that cognition has the same computational architecture from sub-cellular to whole-organism scales. This scale-free architecture supports representations with diverse functions and levels of abstraction.

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