scholarly journals Study of convective structures and phase transition induced in a water layer by non-stationary boundary conditions

2019 ◽  
Vol 1421 ◽  
pp. 012047
Author(s):  
Yu N Dubnishchev ◽  
V A Arbuzov ◽  
E V Arbuzov ◽  
V S Berdnikov ◽  
O S Zolotukhina ◽  
...  
Keyword(s):  
Phase Transition ◽  
Boundary Conditions ◽  
Water Layer ◽  
Stationary Boundary ◽  
Convective Structures

scholarly journals Investigation of convective structures and phase transition induced by non-stationary boundary conditions in a horizontal layer of water

2019 ◽  
Author(s):  
Виталий Арбузов ◽  
Vitaliy Arbuzov ◽  
Эдуард Арбузов ◽  
Eduard Arbuzov ◽  
Владимир Бердников ◽  
...  
Keyword(s):  
Phase Transition ◽  
Boundary Conditions ◽  
Water Layer ◽  
Horizontal Layer ◽  
Temperature Fields ◽  
Special Importance ◽  
Stationary Boundary ◽  
Convective Structures ◽  
Numerical Simulation Methods ◽  
Lower Heat

The evolution of convective structures and the phase transition induced by non-stationary boundary conditions in a horizontal water layer bounded by flat heat-exchange surfaces were studied by shear interferometry and numerical simulation methods. Numerical modeling of the temperature field as a field of isotherms in the mode of monotonous cooling of horizontal walls was performed. The problem of fragmentary reconstruction of hilbertograms and shear interferograms images from a numerical model of the isotherm field was solved. The hydrodynamics of convective currents, the coevolution of temperature fields, interference and Hilbert structures have been modeled and studied taking into account the inversion of water density in the vicinity of the isotherm (+4°C), under conditions of phase transition and growth of the ice layer on the lower heat transfer plane. The simulation was performed using a proprietary software package. The relevance of this kind of research is due to the special importance of convection in geodynamics, physics of the atmosphere and the ocean, in hydrodynamic and thermophysical processes associated with the formation and growth of crystals.

Optical diagnostics of convective structures induced by non-stationary boundary conditions in a vertical water layer

2018 ◽  
Vol 10 (4) ◽  
pp. 134-144 ◽  
Author(s):  
Yu.N. Dubnishchev ◽  
V.A. Arbuzov ◽  
E.V. Arbuzov ◽  
V.S. Berdnikov ◽  
S.A. Kislytsin ◽  
...  
Keyword(s):  
Boundary Conditions ◽  
Optical Diagnostics ◽  
Water Layer ◽  
Stationary Boundary ◽  
Convective Structures

scholarly journals Holographic anisotropic model for light quarks with confinement-deconfinement phase transition

2021 ◽  
Vol 2021 (6) ◽  
Author(s):  
Irina Ya. Aref’eva ◽  
Kristina Rannu ◽  
Pavel Slepov
Keyword(s):  
Phase Transition ◽  
Boundary Conditions ◽  
Chemical Potential ◽  
String Tension ◽  
Isotropic Case ◽  
Holographic Model ◽  
Anisotropic Model ◽  
Dilaton Field ◽  
Cornell Potential ◽  
Qcd Phase Diagram

Abstract We present a five-dimensional anisotropic holographic model for light quarks supported by Einstein-dilaton-two-Maxwell action. This model generalizing isotropic holographic model with light quarks is characterized by a Van der Waals-like phase transition between small and large black holes. We compare the location of the phase transition for Wilson loops with the positions of the phase transition related to the background instability and describe the QCD phase diagram in the thermodynamic plane — temperature T and chemical potential μ. The Cornell potential behavior in this anisotropic model is also studied. The asymptotics of the Cornell potential at large distances strongly depend on the parameter of anisotropy and orientation. There is also a nontrivial dependence of the Cornell potential on the boundary conditions of the dilaton field and parameter of anisotropy. With the help of the boundary conditions for the dilaton field one fits the results of the lattice calculations for the string tension as a function of temperature in isotropic case and then generalize to the anisotropic one.

Thermal phase transition behaviours of the blue phase of bent-core nematogen and chiral dopant mixtures under different boundary conditions

Soft Matter ◽  
2014 ◽  
Vol 10 (41) ◽  
pp. 8224-8228 ◽  
Author(s):  
Min-Jun Gim ◽  
Gohyun Han ◽  
Suk-Won Choi ◽  
Dong Ki Yoon
Keyword(s):  
Phase Transition ◽  
Boundary Conditions ◽  
Liquid Crystalline ◽  
Isotropic Phase ◽  
Different Boundary Conditions ◽  
Various Boundary Conditions ◽  
Thermal Phase Transition ◽  
Thermal Phase ◽  
Blue Phase ◽  
Chiral Dopants

We have investigated dramatic changes in the thermal phase transition of a liquid-crystalline (LC) blue phase (BP) consisting of bent-core nematogen and chiral dopants under various boundary conditions during cooling from the isotropic phase.

scholarly journals Evidence of the Poisson/Gaudin–Mehta phase transition for band matrices on global scales

2018 ◽  
Vol 07 (02) ◽  
pp. 1850002
Author(s):  
Sheehan Olver ◽  
Andrew Swan
Keyword(s):  
Phase Transition ◽  
Boundary Conditions ◽  
Rate Of Convergence ◽  
Critical Behavior ◽  
Level Density ◽  
Boundary Effects ◽  
Fourth Moment ◽  
Band Matrices ◽  
Band Matrix ◽  
Symmetric Band

We prove that the Poisson/Gaudin–Mehta phase transition conjectured to occur when the bandwidth of an [Formula: see text] symmetric band matrix grows like [Formula: see text] is naturally observable in the rate of convergence of the level density to the Wigner semi-circle law. Specifically, we show for periodic and non-periodic band matrices the rate of convergence of the fourth moment of the level density is independent of the boundary conditions in the localized regime [Formula: see text] with a rate of [Formula: see text] for both cases, whereas in the delocalized regime [Formula: see text] where boundary effects become important, the rate of convergence for the two ensembles differs significantly, slowing to [Formula: see text] for non-periodic band matrices. Additionally, we examine the case of thick non-periodic band matrices [Formula: see text], showing that the fourth moment is maximally deviated from the Wigner semi-circle law when [Formula: see text], and provide numerical evidence that the eigenvector statistics also exhibit critical behavior at this point.

scholarly journals Properties of size-dependent models having quasiperiodic boundary conditions

2018 ◽  
Vol 33 (01) ◽  
pp. 1850008 ◽  
Author(s):  
E. Cavalcanti ◽  
C. A. Linhares ◽  
A. P. C. Malbouisson
Keyword(s):  
Phase Transition ◽  
Boundary Condition ◽  
Boundary Conditions ◽  
Thermal Equilibrium ◽  
Periodic Boundary Condition ◽  
Periodic Boundary ◽  
Minimal Length ◽  
Thermally Induced ◽  
Size Dependent ◽  
Aharonov Bohm

Boundary condition effects are explored for size-dependent models in thermal equilibrium. Scalar and fermionic models are used for [Formula: see text] (films), [Formula: see text] (hollow cylinder) and [Formula: see text] (ring). For all models, a minimal length is found, below which no thermally-induced phase transition occurs. Using quasiperiodic boundary condition controlled by a contour parameter [Formula: see text] ([Formula: see text] is a periodic boundary condition and [Formula: see text] is an antiperiodic condition), it results that the minimal length depends directly on the value of [Formula: see text]. It is also argued that this parameter can be associated to an Aharonov–Bohm phase.

scholarly journals AN OPEN INFLATIONARY MODEL FOR DIMENSIONAL REDUCTION AND ITS EFFECTS ON THE OBSERVABLE PARAMETERS OF THE UNIVERSE

2005 ◽  
Vol 20 (11) ◽  
pp. 2449-2453
Author(s):  
KORAY KARACA ◽  
SELÇUK BAYIN
Keyword(s):  
Phase Transition ◽  
Cosmological Model ◽  
Boundary Conditions ◽  
Dimensional Reduction ◽  
Higher Dimensions ◽  
Inflationary Model ◽  
Early Stages ◽  
Isotropic Cosmological Model ◽  
Spatially Homogeneous ◽  
The Universe

Assuming that higher dimensions existed in the early stages of the universe where the evolution was inflationary, we construct an open, singularity-free, spatially homogeneous and isotropic cosmological model to study the effects of dimensional reduction that may have taken place during the early stages of the universe. We consider dimensional reduction to take place in a stepwise manner and interpret each step as a phase transition. By imposing suitable boundary conditions we trace their effects on the present day parameters of the universe.

A New Method to Simulate Rotor-Stator Interactions in a Centrifugal Pump Stage

2006 ◽  
Author(s):  
Jianjun Feng ◽  
Friedrich-Karl Benra ◽  
Hans Josef Dohmen
Keyword(s):  
Boundary Conditions ◽  
Centrifugal Pump ◽  
Mass Flow ◽  
New Method ◽  
Water Tank ◽  
Mean Flow ◽  
Vaned Diffuser ◽  
Stationary Boundary ◽  
Flow Fluctuation ◽  
Return Channel

A new method is put forward to model rotor-stator interactions in the first stage of a multistage centrifugal pump consisting of an impeller, a vaned diffuser and a vaned return channel. A directional loss model is utilized to model the function of a water tank behind the return channel. A periodic boundary condition between the inlet and the outlet is applied to model a closed loop. Thus no flow specification either in the inlet or outlet is required, neither is the turbulence level. Consequently it can avoid specifying unphysical stationary boundary conditions at the inlet and the outlet for transient simulations. Transient numerical results are compared with those by the conventional simulation with stationary boundary conditions (constant total pressure at the inlet and fixed mass flow at the outlet) in detail. The new model can predict the mass flow fluctuation in the pump, which reaches 0.5% of mean flow rate during one period. The mass flow fluctuation does not have a significant influence on the velocity field; however it does have some important effects on the pressure and turbulent kinetic energy fields.

Sign in / Sign up

Export Citation Format

Share Document