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.

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.

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

scholarly journals Flushing and Locking of Venous Catheters: Available Evidence and Evidence Deficit

2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
Godelieve Alice Goossens
Keyword(s):  
Fluid Dynamics ◽  
Sodium Chloride ◽  
Clinical Sign ◽  
Chelating Agents ◽  
Antithrombotic Effect ◽  
Catheter Occlusion ◽  
Catheter Malfunction ◽  
Long Time ◽  
Catheter Lock ◽  
Intravenous Catheters

Flushing and locking of intravenous catheters are thought to be essential in the prevention of occlusion. The clinical sign of an occlusion is catheter malfunction and flushing is strongly recommended to ensure a well-functioning catheter. Therefore fluid dynamics, flushing techniques, and sufficient flushing volumes are important matters in adequate flushing in all catheter types. If a catheter is not in use, it is locked. For years, it has been thought that the catheter has to be filled with an anticoagulant to prevent catheter occlusion. Heparin has played a key role in locking venous catheters. However, the high number of risks associated with heparin forces us to look for alternatives. A long time ago, 0.9% sodium chloride was already introduced as locking solution in peripheral cannulas. More recently, a 0.9% sodium chloride lock has also been investigated in other types of catheters. Thrombolytic agents have also been studied as a locking solution because their antithrombotic effect was suggested as superior to heparin. Other catheter lock solutions focus on the anti-infective properties of the locks such as antibiotics and chelating agents. Still, the most effective locking solution will depend on the catheter type and the patient’s condition.

scholarly journals TIME-DEPENDENT RESCALINGS AND LYAPUNOV FUNCTIONALS FOR THE VLASOV–POISSON AND EULER–POISSON SYSTEMS, AND FOR RELATED MODELS OF KINETIC EQUATIONS, FLUID DYNAMICS AND QUANTUM PHYSICS

2001 ◽  
Vol 11 (03) ◽  
pp. 407-432 ◽  
Author(s):  
J. DOLBEAULT ◽  
G. REIN
Keyword(s):  
Fluid Dynamics ◽  
Quantum Physics ◽  
Kinetic Equations ◽  
Euler System ◽  
Lyapunov Functionals ◽  
Time Behavior ◽  
Long Time Behavior ◽  
Poisson System ◽  
Dispersion Effects ◽  
Long Time

We investigate rescaling transformations for the Vlasov–Poisson and Euler–Poisson systems and derive in the plasma physics case Lyapunov functionals which can be used to analyze dispersion effects. The method is also used for studying the long time behavior of the solutions and can be applied to other models in kinetic theory (two-dimensional symmetric Vlasov–Poisson system with an external magnetic field), in fluid dynamics (Euler system for gases) and in quantum physics (Schrödinger–Poisson system, nonlinear Schrödinger equation).

scholarly journals On the Hamiltonian approach: Applications to geophysical flows

1998 ◽  
Vol 5 (4) ◽  
pp. 219-240 ◽  
Author(s):  
V. Goncharov ◽  
V. Pavlov
Keyword(s):  
Degrees Of Freedom ◽  
Fluid Motion ◽  
Gauge Transformations ◽  
Motion Models ◽  
Canonical Variables ◽  
Long Time ◽  
Minimum Number ◽  
Nonlinear Gauge ◽  
Hydrodynamical System ◽  
General Method

Abstract. This paper presents developments of the Harniltonian Approach to problems of fluid dynamics, and also considers some specific applications of the general method to hydrodynamical models. Nonlinear gauge transformations are found to result in a reduction to a minimum number of degrees of freedom, i.e. the number of pairs of canonically conjugated variables used in a given hydrodynamical system. It is shown that any conservative hydrodynamic model with additional fields which are in involution may be always reduced to the canonical Hamiltonian system with three degrees of freedom only. These gauge transformations are associated with the law of helicity conservation. Constraints imposed on the corresponding Clebsch representation are determined for some particular cases, such as, for example. when fluid motions develop in the absence of helicity. For a long time the process of the introduction of canonical variables into hydrodynamics has remained more of an intuitive foresight than a logical finding. The special attention is allocated to the problem of the elaboration of the corresponding regular procedure. The Harniltonian Approach is applied to geophysical models including incompressible (3D and 2D) fluid motion models in curvilinear and lagrangian coordinates. The problems of the canonical description of the Rossby waves on a rotating sphere and of the evolution of a system consisting of N singular vortices are investigated.

scholarly journals On the Relation between the Rotation of the Earth and Solar Activity

1972 ◽  
Vol 48 ◽  
pp. 231-233
Author(s):  
Chikara Sugawa ◽  
Chuichi Kakuta ◽  
Hideo Matsukura
Keyword(s):  
Solar Activity ◽  
Solid Earth ◽  
Polar Motion ◽  
Rotational Velocity ◽  
Lower Atmosphere ◽  
Neutral Atmosphere ◽  
Symmetric Mode ◽  
Axially Symmetric ◽  
The Earth ◽  
Long Time

Solar activity may affect the rotation of the solid Earth by coupling between the lower neutral atmosphere and the solid Earth. It attacks directly the lower atmosphere in the non-axially symmetric mode and may trigger off variation of the amplitude of the annual terms in the polar motion. The indirect effect of solar activity may be associated with some proper oscillation of the atmospheric coupling with the ocean in the axially symmetric mode of the atmospheric motion. The shift of airmass along the rotating axis of the Earth corresponds well with the changes of the Earth's rotational velocity and the Chandler amplitude in the polar motion for long time variation.

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