arXiv subjects

Shouhong Wang

Publications and source records attributed to Shouhong Wang.

45 records · Page 3Linked to original sources

arXiv2007

Dynamic Phase Transitions in Superconductivity

In this Letter, the dynamic phase transitions of the time-dependent Ginzburg-Landau equations are analyzed using a newly developed dynamic transition theory and a new classification scheme of dynamics phase transitions. First, we demonstrate that there are two type of dynamic transitions, jump and continuous, dictated by the sign of a nondimensional parameter R. This parameter is computable, and depends on the material property, the applied field, and the geometry of domain that the sample occupies. Second, using the parameter R, precise analytical formulas for critical domain size, and for critical magnetic fields are derived.

cond-mat.supr-con↗

arXiv2007

Addendum to the paper "Two-Dimensional Infinite Prandtl Number Convection: Structure of Bifurcated Solutions, J. Nonlinear Sci., 17(3), 199-220, 2007"

The main objective of this addendum to the mentioned article by Park is to provide some remarks on bifurcation theories for nonlinear partial differential equations (PDE) and their applications to fluid dynamics problems. We only wish to comment and list some related literatures, without any intention to provide a complete survey.

math-ph↗

arXiv2007

Rayleigh-Benard Convection: Dynamics and Structure in the Physical Space

The main objective of this article is part of a research program to link the dynamics of fluid flows with the structure and its transitions in the physical spaces. As a prototype of problem and to demonstrate the main ideas, we study the two-dimensional Rayleigh-Benard convection. The analysis is based on two recently developed nonlinear theories: geometric theory for incompressible flows [10] and the bifurcation and stability theory for nonlinear dynamical systems (both finite and infinite dimensional) [9]. We have shown in [8] that the Rayleigh-Benard problem bifurcates from the basic state to an attractor A_R when the Rayleigh number R crosses the first critical Rayleigh number R_c for all physically sound boundary conditions, regardless of the multiplicity of the eigenvalue R_c for the linear problem. In this article, in addition to a classification of the bifurcated attractor A_R, the structure and its transitions of the solutions in the physical space is classified, leading to the existence and stability of two different flows structures: pure rolls and rolls separated by a cross the channel flow. It appears that the structure with rolls separated by a cross channel flow has not been carefully examined although it has been observed in other physical contexts such as the Branstator-Kushnir waves in the atmospheric dynamics [1,7].

math.AP↗

arXiv2007

Formation and Persistence of Spatiotemporal Turing Patterns

This article is concerned with the stability and long-time dynamics of structures arising from a structureless state. The paradigm is suggested by developmental biology, where morphogenesis is thought to result from a competition between chemical reactions and spatial diffusion. A system of two reaction-diffusion equations for the concentrations of two morphogens is reduced to a finite system of ordinary differential equations. The stability of bifurcated solutions of this system is analyzed, and the long-time asymptotic behavior of the bifurcated solutions is established rigorously. The Schnakenberg and Gierer-Meinhardt equations are discussed as examples.

nlin.PS↗

arXiv2007

Boundary-Layer and Interior Separations in the Taylor--Couette--Poiseuille Flow

In this article, we derive a rigorous characterization of the boundary-layer and interior separations in the Taylor-Couette-Poiseuille (TCP) flow. The results obtained provide a rigorous characterization on how, when and where the propagating Taylor vortices (PTV) are generated. In particular, contrary to what is commonly believed, we show that the PTV do not appear after the first dynamical bifurcation, and they appear only when the Taylor number is further increased to cross another critical value so that a structural bifurcation occurs. This structural bifurcation corresponds to the boundary-layer and interior separations of the flow structure in the physical space.

math-ph↗

arXiv2007

Stratified Rotating Boussinesq Equations in Geophysical Fluid Dynamics: Dynamic Bifurcation and Periodic Solutions

The main objective of this article is to study the dynamics of the stratified rotating Boussinesq equations, which are a basic model in geophysical fluid dynamics. First, for the case where the Prandtl number is greater than one, a complete stability and bifurcation analysis near the first critical Rayleigh number is carried out. Second, for the case where the Prandtl number is smaller than one, the onset of the Hopf bifurcation near the first critical Rayleigh number is established, leading to the existence of nontrivial periodic solutions. The analysis is based on a newly developed bifurcation and stability theory for nonlinear dynamical systems (both finite and infinite dimensional) by two of the authors [16].

math-ph↗

arXiv2006

Attractor Bifurcation of Three-Dimensional Double-Diffusive Convection

In this article, we present a bifurcation analysis on the double-diffusive convection. Two pattern selections, rectangles and squares, are investigated. It is proved that there are two different types of attractor bifurcations depending on the thermal and salinity Rayleigh numbers for each pattern. The analysis is based on a newly developed attractor bifurcation theory, together with eigen-analysis and the center manifold reductions.

nlin.PS↗

arXiv2006

Bifurcation and Stability of Two-Dimensional Double-Diffusive Convection

In this article, we present a bifurcation and stability analysis on the double-diffusive convection. The main objective is to study 1) the mechanism of the saddle-node bifurcation and hysteresis for the problem, 2) the formation, stability and transitions of the typical convection structures, and 3) the stability of solutions. It is proved in particular that there are two different types of transitions: continuous and jump, which are determined explicitly using some physical relevant nondimensional parameters. It is also proved that the jump transition always leads to the existence of a saddle-node bifurcation and hysteresis phenomena.

physics.ao-ph↗

arXiv1993

Inertial Forms of Navier-Stokes Equations on Sphere

The Navier--Stokes equations for incompressible flows past a two--dimensional sphere are considered in this article. The existence of an inertial form of the equations is established. Furthermore for the first time for fluid equations, we derive an upper bound on the dimension of the differential system (inertial manifold) which fully reproduces the infinite dimensional dynamics. This bound is expressed in terms of Grashof Numbers.

chao-dyn↗