Slow Motion of Gradient Flows PREPRINT. PLEASE DO NOT DISTRIBUTE
نویسندگان
چکیده
We present sufficient conditions on an energy landscape in order for the associated gradient flow to exhibit slow motion or “dynamic metastability.” The first condition is a weak form of convexity transverse to the so-called slow manifold, N . The second condition is that the energy restricted to N is Lipschitz with a constant δ ¿ 1. One feature of the abstract result that makes it of broader interest is that it does not rely on maximum principles. As an application, we give a new proof of the exponentially slow motion of transition layers in the one-dimensional Allen-Cahn equation. The analysis is more nonlinear than previous work: It relies on the nonlinear convexity condition or “energy-energy-dissipation inequality.” (Although we do use the maximum principle for convenience in the application, we believe it may be removed with additional work.) Our result demonstrates that a broad class of initial data relaxes with an exponential rate into a δ-neighborhood of the slow manifold, where it is then trapped for an exponentially long time.
منابع مشابه
Diffusive transport in two-dimensional nematics
We discuss a dynamical theory for nematic liquid crystals describing the stage of evolution in which the hydrodynamic fluid motion has already equilibrated and the subsequent evolution proceeds via diffusive motion of the orientational degrees of freedom. This diffusion induces a slow motion of singularities of the order parameter field. Using asymptotic methods for gradient flows, we establish...
متن کاملExistence and Uniqueness of the Gradient Flow of the Entropy in the Space of Probability Measures
After a brief introduction on gradient flows in metric spaces and on geodesically convex functionals, we give an account of the proof (following the outline of [3, 7]) of the existence and uniqueness of the gradient flow of the Entropy in the space of Borel probability measures over a compact geodesic metric space with Ricci curvature bounded from below. Preprint SISSA 17/2014/MATE
متن کاملSlow inviscid flows of a compressible fluid in spatially inhomogeneous systems.
An ideal compressible fluid is considered, with an equilibrium density being a given function of coordinates due to presence of some static external forces. The slow flows in such system, which do not disturb the density, are investigated with the help of the Hamiltonian formalism. The equations of motion of the system are derived for an arbitrary given topology of the vorticity field. The gene...
متن کاملSome isoperimetric results concerning undirectional flows in microchannels
At a given pressure gradient, for all channels with given area, that which maximises the steady flow Qsteady has a circular cross-section. Consider flows starting from rest developing from a constant imposed pressure gradient: for all channels with given crosssectional area, that which has the slowest approach to the steady flow is the circular disk cross-section. This arXiv preprint will suppl...
متن کاملElectro-magneto-hydrodynamics Flows of Burgers' Fluids in Cylindrical Domains with Time Exponential Memory
This paper investigates the axial unsteady flow of a generalized Burgers’ fluid with fractional constitutive equation in a circular micro-tube, in presence of a time-dependent pressure gradient and an electric field parallel to flow direction and a magnetic field perpendicular on the flow direction. The mathematical model used in this work is based on a time-nonlocal constitutive equation for s...
متن کاملEffects of Brownian motion and Thermophoresis on MHD Mixed Convection Stagnation-point Flow of a Nanofluid Toward a Stretching Vertical Sheet in Porous Medium
This article deals with the study of the two-dimensional mixed convection magnetohydrodynamic (MHD) boundary layer of stagnation-point flow over a stretching vertical plate in porous medium filled with a nanofluid. The model used for the nanofluid incorporates the effects of Brownian motion and thermophoresis in the presence of thermal radiation. The skin-friction coefficient, Nusselt number an...
متن کامل