Rigorous determination of the disintegration temperature of single vortex lines

1991 ◽  
Vol 181 (1-3) ◽  
pp. 163-170 ◽  
Author(s):  
Gregor Hackenbroich ◽  
Stefan Scheidl
Keyword(s):  
Single Vortex ◽  
Vortex Lines

scholarly journals I. On the motion of fluid, part of which is moving rotationally and part irrotationally

1883 ◽  
Vol 36 (228-231) ◽  
pp. 276-284 ◽  
Keyword(s):  
Single Equation ◽  
Plane Motion ◽  
Vortex Lines ◽  
Irrotational Motion

Clebsch has show that the components of the velocity of a fluid u, v, w , parallel to rectangular axes x, y, z , may always be expressed thus— u = dX / dx + λ dψ / dx . v = dX / dy + λ dψ / dy , w = dX / dz +λ dψ / dz ; Where λ, ψ are systems of surfaces whose intersections determine the vortex lines; and the pressure satisfies an equation which is equivalent to the following— p /ρ + V = - dX / dt -1/2{( dX / dx ) 2 + ( dX / dy ) 2 + ( dX / dz ) 2 } + 1/2 λ 2 {( dψ / dx ) 2 + ( dψ / dy ) 2 + ( dψ / dz ) 2 } where p is the pressure, ρ the density, and V the potential of the forces acting on the liquid. It is shown in this paper that an equation in λ only can be obtained in the following cases (that is to say, as in cases of irrotational motion, the determination of the motion depends on the solution of a single equation only):— (1.) Plane motion, referred to rectangular co-ordinates x , y .

Nucleation of single vortex lines in rotating3He-B

1994 ◽  
Vol 194-196 ◽  
pp. 771-772 ◽  
Author(s):  
U¨. Parts ◽  
J.H. Koivuniemi ◽  
M. Krusius ◽  
V.M.H. Ruutu ◽  
S.R. Zakazov
Keyword(s):  
Single Vortex ◽  
Vortex Lines

Streamwise vortices and transition to turbulence

1994 ◽  
Vol 264 ◽  
pp. 185-212 ◽  
Author(s):  
James M. Hamilton ◽  
Frederick H. Abernathy
Keyword(s):  
Streamwise Velocity ◽  
Transition To Turbulence ◽  
Streamwise Vortices ◽  
Single Vortex ◽  
Transitional Flows ◽  
Vortex Interactions ◽  
Crossflow Velocity ◽  
Series Of Experiments ◽  
Made In

A series of experiments was conducted to determine the conditions under which streamwise vortices can cause transition to turbulence in shear flows. A specially designed obstacle was used to produce a single vortex in a water-table flow, and the design of this obstacle is discussed. Laser-Doppler velocimetry measurements of the streamwise and crossflow velocity fields were made in transitional and non-transitional flows, and flow visualization was also used. It was found that strong vortices (vortices with large circulation) lead to turbulence while weaker vortices do not. Determination of a critical value of vortex strength for transition, however, was complicated by ambiguities in calculating the vortex circulation. The profiles of streamwise velocity were found to be inflexional for both transitional and non-transitional flows. Transition in single-vortex and multi-vortex flows was compared, and no qualitative differences were observed, suggesting no significant vortex interactions affecting transition.

scholarly journals XX. The potential of an anchor ring.-Part II

1893 ◽  
Vol 184 ◽  
pp. 1041-1106 ◽  
Keyword(s):  
Vortex Ring ◽  
Cross Section ◽  
Steady Motion ◽  
Vortex Rings ◽  
Laplace’S Equation ◽  
Single Vortex ◽  
Laplace's Equation ◽  
The Stability ◽  
Work Done

This paper is a continuation of that at pp. 43-95 suprd , on “The Potential of an Anchor Bing.” In that paper the potential of an anchor ring was found at all external points; in this/its value is determined at internal points. The annular form of rotating gravitating fluid was also discussed in that paper; here the stability of such a ring is considered. In addition, the potential of a ring whose cross-section is elliptic, being of interest in connection with Saturn, is obtained. The similarity of the methods employed, as well as of the analysis, has led me to give in this paper also a determination of the steady motion of a single vortex-ring in an infinite fluid, and of several fine vortex rings on the same axis. In Section I. solutions of Laplace’s equation applicable to space inside an anchor ring are obtained. These results are applied to obtain the potential of a solid ring at internal points, and also of a distribution of matter on the surface of the ring. The work done in collecting the ring from infinity is obtained.

Real-Time Dynamics of Single Vortex Lines and Vortex Dipoles in a Bose-Einstein Condensate

Science ◽  
2010 ◽  
Vol 329 (5996) ◽  
pp. 1182-1185 ◽  
Author(s):  
D. V. Freilich ◽  
D. M. Bianchi ◽  
A. M. Kaufman ◽  
T. K. Langin ◽  
D. S. Hall
Keyword(s):  
Real Time ◽  
Einstein Condensate ◽  
Single Vortex ◽  
Time Dynamics ◽  
Vortex Dipoles ◽  
Bose Einstein Condensate ◽  
Vortex Lines ◽  
Bose Einstein

Observations on Single Vortex Lines in Rotating Superfluid Helium

1972 ◽  
Vol 6 (2) ◽  
pp. 799-807 ◽  
Author(s):  
Richard E. Packard ◽  
T. M. Sanders
Keyword(s):  
Superfluid Helium ◽  
Single Vortex ◽  
Vortex Lines

Determination of pinning forces on vortex lines in YBa2Cu3O7-delta

1999 ◽  
Vol 12 (12) ◽  
pp. 1090-1093 ◽  
Author(s):  
J H Durrell ◽  
R Herzog ◽  
P Berghuis ◽  
A P Bramley ◽  
E J Tarte ◽  
...  
Keyword(s):  
Vortex Lines

XVI. On the motion of fluid, part of which is moving rotationally and part irrotationally

1884 ◽  
Vol 175 ◽  
pp. 363-409 ◽  
Keyword(s):  
Single Equation ◽  
Plane Motion ◽  
Vortex Lines ◽  
Rectangular Coordinates ◽  
Irrotational Motion ◽  
Arbitrary Velocity ◽  
Complicated Nature

Clebsch has shown that the components of the velocity of a fluid u , v , w , parallel to rectangular axes x , y , z , may always be expressed thus u = dχ / dx + λ dΨ / dx , v = dχ / dy + λ dΨ / dy , w = dχ / dz + λ dΨ / dz ; where λ, Ψ are systems of surfaces whose intersections determine the vortex lines; and the pressure satisfies an equation which is equivalent to the following p / ρ + V = – dχ / dt –½{( dχ / dx ) 2 + ( dχ / dy ) 2 +( dχ / dz ) 2 } + ½ λ 2 {( dΨ / dx ) 2 +( dΨ / dy ) 2 +( dΨ / dz ) 2 } where p is the pressure, ρ the density, and V the potential of the forces acting on the liquid. It is shown in this paper that an equation of a complicated nature in λ only can be obtained in the following cases (that is to say, as in cases of irrotational motion, the determination of the motion depends on the solution of a single equation only):— (1.) Plane motion, referred to rectangular coordinates x , y . The equation is somewhat simpler when the vortex surfaces are of invariable form, and move parallel to one of the axes of coordinates with arbitrary velocity.

scholarly journals Helicity and singular structures in fluid dynamics

2014 ◽  
Vol 111 (10) ◽  
pp. 3663-3670 ◽  
Author(s):  
H. Keith Moffatt
Keyword(s):  
Stokes Equations ◽  
Minimum Energy ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Low Reynolds Number Flows ◽  
Vortex Lines ◽  
Quadratic Invariant ◽  
Euler Flows

Helicity is, like energy, a quadratic invariant of the Euler equations of ideal fluid flow, although, unlike energy, it is not sign definite. In physical terms, it represents the degree of linkage of the vortex lines of a flow, conserved when conditions are such that these vortex lines are frozen in the fluid. Some basic properties of helicity are reviewed, with particular reference to (i) its crucial role in the dynamo excitation of magnetic fields in cosmic systems; (ii) its bearing on the existence of Euler flows of arbitrarily complex streamline topology; (iii) the constraining role of the analogous magnetic helicity in the determination of stable knotted minimum-energy magnetostatic structures; and (iv) its role in depleting nonlinearity in the Navier-Stokes equations, with implications for the coherent structures and energy cascade of turbulence. In a final section, some singular phenomena in low Reynolds number flows are briefly described.

Galactic orbits of stars

1966 ◽  
Vol 25 ◽  
pp. 93-97
Author(s):  
Richard Woolley
Keyword(s):  
Globular Cluster ◽  
Potential Field ◽  
High Velocity ◽  
Velocity Vector ◽  
Variable Stars ◽  
The Sun ◽  
Proper Motions ◽  
Rr Lyrae ◽  
The Galaxy

It is now possible to determine proper motions of high-velocity objects in such a way as to obtain with some accuracy the velocity vector relevant to the Sun. If a potential field of the Galaxy is assumed, one can compute an actual orbit. A determination of the velocity of the globular clusterωCentauri has recently been completed at Greenwich, and it is found that the orbit is strongly retrograde in the Galaxy. Similar calculations may be made, though with less certainty, in the case of RR Lyrae variable stars.

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