Whether the two-dimensional Eulerian turbulence evolves to a unique final state

2002 ◽  
Vol 14 (11) ◽  
pp. 3937-3945 ◽  
Author(s):  
V. Pavlov ◽  
D. Buisine ◽  
S. Decossin
Keyword(s):  
Two Dimensional ◽  
Final State

Axisymmetrization and vorticity-gradient intensification of an isolated two-dimensional vortex through filamentation

1987 ◽  
Vol 178 ◽  
pp. 137-159 ◽  
Author(s):  
M. V. Melander ◽  
J. C. Mcwilliams ◽  
N. J. Zabusky
Keyword(s):  
Aspect Ratio ◽  
Second Order ◽  
Rate Of Change ◽  
Two Dimensional ◽  
Final State ◽  
Diagnostic Algorithms ◽  
Dissipative Fluid ◽  
New Formula ◽  
Corotating Frame

We consider the evolution of an isolated elliptical vortex in a weakly dissipative fluid. It is shown computationally that a spatially smooth vortex relaxes inviscidly towards axisymmetry on a circulation timescale as the result of filament generation. Heuristically, we derive a simple geometrical formula relating the rate of change of the aspect ratio of a particular vorticity contour to its orientation relative to the streamlines (where the orientation is defined through second-order moments). Computational evidence obtained with diagnostic algorithms validates the formula. By considering streamlines in a corotating frame and applying the new formula, we obtain a detailed kinematic understanding of the vortex's decay to its final state through a primary and a secondary breaking. The circulation transported into the filaments although a small fraction of the total, breaks the symmetry and is the chief cause of axisymmetrization.

scholarly journals Universality of Final State in Two Dimensional Dilaton Cosmology

1993 ◽  
Vol 90 (3) ◽  
pp. 689-704
Author(s):  
M. Hotta ◽  
Y. Suzuki ◽  
Y. Tamiya ◽  
M. Yoshimura
Keyword(s):  
Two Dimensional ◽  
Final State

scholarly journals Idealized Two-Dimensional Modeling of a Coastal Buoyancy Front, or River Plume, under Downwelling-Favorable Wind Forcing with Application to the Alaska Coastal Current

2010 ◽  
Vol 40 (2) ◽  
pp. 279-294 ◽  
Author(s):  
William J. Williams ◽  
Thomas J. Weingartner ◽  
Albert J. Hermann
Keyword(s):  
Wind Stress ◽  
River Plume ◽  
Coastal Current ◽  
Two Dimensional ◽  
Coriolis Parameter ◽  
Final State ◽  
Bottom Boundary Layers ◽  
The Cross ◽  
Alaska Coastal Current ◽  
Bottom Depth

Abstract The cross-shelf structure of a buoyancy-driven coastal current, such as produced by a river plume, is modeled in a two-dimensional cross-shelf slice as a “wide” geostrophically balanced buoyancy front. Downwelling-favorable wind stress applied to this front leads to advection in the surface and bottom boundary layers that causes the front to become steeper so that it eventually reaches a steep quasi-steady state. This final state is either convecting, stable and steady, or stable and oscillatory depending on D/δ* and by /f 2, where D is bottom depth, δ* is an Ekman depth, by is the cross-shelf buoyancy gradient, and f is the Coriolis parameter. Descriptions of the cross-shelf circulation patterns are given and a scaling is presented for the isopycnal slope. The results potentially apply to the Alaska Coastal Current, which experiences strong, persistent downwelling-favorable wind stress during winter, but also likely have application to river plumes subjected to downwelling-favorable wind stress.

QUANTUM BLACK HOLES, STRINGS AND σ-MODELS AT θ=π: HAWKING QUANTUM EVAPORATION AS WORLD-SHEET RG-FLOW

1991 ◽  
Vol 06 (36) ◽  
pp. 3297-3311 ◽  
Author(s):  
IAN I. KOGAN
Keyword(s):  
Black Holes ◽  
Renormalization Group ◽  
Fixed Points ◽  
Quantum Hall ◽  
Conformal Factor ◽  
Two Dimensional ◽  
Stable States ◽  
World Sheet ◽  
Final State ◽  
Quantum Evaporation

We discuss the quantum black holes and even more generally the problem of quantum horizons in string theory. A toy model for quantum horizon is the two-dimensional O(3) σ-model. Using the interpretation of time as zero mode of conformal factor of world-sheet metric (Liouville field) the possible equivalence between two-dimensional renormalization group equations and Hawking quantum evaporation formula is found. The infrared fixed points of two-dimensional renormalization group corresponds to final state of the quantum black hole. Using conjecture that such a fixed points are described by σ-models with θ=π we suggest the axionic black holes as possible candidates to final (meta)stable states of black holes. The corresponding renormalization group picture are similar to the quantum Hall effect.

scholarly journals Formation of vortex clusters on a sphere

2001 ◽  
Vol 8 (1/2) ◽  
pp. 9-19 ◽  
Author(s):  
V. Pavlov ◽  
D. Buisine ◽  
V. Goncharov
Keyword(s):  
Numerical Analysis ◽  
Initial Conditions ◽  
Equations Of Motion ◽  
Two Dimensional ◽  
Hamiltonian Approach ◽  
Governing Equations ◽  
Helmholtz Instability ◽  
Final State ◽  
Large N ◽  
Long Time

Abstract. This paper applies the Hamiltonian Approach (HA) to two-dimensional motions of incompressible fluid in curvi-linear coordinates, in particular on a sphere. The HA has been used to formulate governing equations of motion and to interpret the evolution of a system consisting of N localized two-dimensional vortices on a sphere. If the number of vortices N is large,  N ~ 102 - 103 , a small number of vortex collective structures (clusters) is formed. The surprise is that a quasi-final state does not correspond to completely disorganized distribution of vorticity. Numerical analysis has been carried out for initial conditions taken in the form of a few axisymmetric chains of point vortices distributed initially in fixed latitudes. The scheme of Runge-Kutta of 4th order has been used for simulating an evolution of resulting flows. The numerical analysis shows that the Kelvin-Helmholtz instability appears immediately formating initial disorganized structures which are developed and finally "bursted". The system evolves to a few separated vortex "spots" which exist sufficiently for a long time.

scholarly journals Orbit classification in exoplanetary systems

2020 ◽  
Vol 634 ◽  
pp. A60 ◽  
Author(s):  
Euaggelos E. Zotos ◽  
Bálint Érdi ◽  
Tareq Saeed ◽  
Mohammed Sh. Alhodaly
Keyword(s):  
Test Particle ◽  
Dynamical Behavior ◽  
Major Axis ◽  
Two Dimensional ◽  
Semi Major Axis ◽  
Final State ◽  
Exoplanetary Systems ◽  
Primary Body ◽  
Starting Conditions ◽  
Three Body

The circular version of the restricted three-body problem, along with the method of grid classification are used to determine the character of the trajectories of a test particle, which move in a binary exoplanetary system. The binary system can be either a parent star-exoplanet or an exoplanet–exoplanet or exomoon, while the test particle is considered to be an asteroid or comet, a space probe, or even a small exomoon in the case where the primary body is a star. By using modern two-dimensional color maps, we succeeded in classifying the starting conditions and distinguishing between bounded, escaping, and collision type of motion for the test particle. Furthermore, in the case of bounded regular motion, we further classify the starting conditions by considering their geometry (revolving around one or both main bodies) and orientation (prograde or retrograde, with respect to a rotating coordinate system of the primaries). For the initial setup of the test particle we consider two starting conditions: the launch from pericenter or apocenter. The final states are qualitatively visualized through two-dimensional basin diagrams. This approach allowed us to systematically investigate and extract dynamical information on the dependency of the test particle final state as a function of the particle’s initial semi-major axis and eccentricity for a given primary and secondary mass ratio. Finally, we applied the restricted three-body model on several exoplanetary systems with observed mass-ratios and studied the dynamical behavior of a test-mass.

scholarly journals Analysis of the two dimensional sheet debris flight equations: initial and final state

2010 ◽  
Vol 13 (2) ◽  
pp. 109-125 ◽  
Author(s):  
A. Scarabino ◽  
P. Giacopinelli
Keyword(s):  
Two Dimensional ◽  
Final State

Spectrophotometric measurements of objective-prism spectra

1966 ◽  
Vol 24 ◽  
pp. 118-119
Author(s):  
Th. Schmidt-Kaler
Keyword(s):  
Progress Report ◽  
Two Dimensional ◽  
Objective Prism ◽  
Made In

I should like to give you a very condensed progress report on some spectrophotometric measurements of objective-prism spectra made in collaboration with H. Leicher at Bonn. The procedure used is almost completely automatic. The measurements are made with the help of a semi-automatic fully digitized registering microphotometer constructed by Hög-Hamburg. The reductions are carried out with the aid of a number of interconnected programmes written for the computer IBM 7090, beginning with the output of the photometer in the form of punched cards and ending with the printing-out of the final two-dimensional classifications.

Introductory paper

1966 ◽  
Vol 24 ◽  
pp. 3-5
Author(s):  
W. W. Morgan
Keyword(s):  
Line Intensity ◽  
Classification Scheme ◽  
Two Dimensional ◽  
Spectral Classification ◽  
Dimensional Array ◽  
Rr Lyrae ◽  
Metallic Line ◽  
Introductory Paper ◽  
Parameter Varying ◽  
Definition Of

1. The definition of “normal” stars in spectral classification changes with time; at the time of the publication of theYerkes Spectral Atlasthe term “normal” was applied to stars whose spectra could be fitted smoothly into a two-dimensional array. Thus, at that time, weak-lined spectra (RR Lyrae and HD 140283) would have been considered peculiar. At the present time we would tend to classify such spectra as “normal”—in a more complicated classification scheme which would have a parameter varying with metallic-line intensity within a specific spectral subdivision.

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