arXiv subjects

V. Berti

Publications and source records attributed to V. Berti.

3 recordsLinked to original sources

arXiv2011

A non isothermal phase-field model for the ferromagnetic transition

We propose a model for non isothermal ferromagnetic phase transition based on a phase field approach, in which the phase parameter is related but not identified with the magnetization. The magnetization is split in a paramagnetic and in a ferromagnetic contribution, dependent on a scalar phase parameter and identically null above the Curie temperature. The dynamics of the magnetization below the Curie temperature is governed by the order parameter evolution equation and by a Landau-Lifshitz type equation for the magnetization vector. In the simple situation of a uniaxial magnet it is shown how the order parameter dynamics reproduces the hysteresis effect of the magnetization.

cond-mat.other↗

arXiv2010

A phase field model for liquid-vapour phase transitions

We propose a model describing the liquid-vapour phase transition according to a phase-field approach. The model takes up a setting proposed by the second author, where a phase field is introduced whose equilibrium values 0 and 1 are associated to the liquid and vapour phases. The phase field obeys Ginzburg-Landau equation and enters the constitutive relation of the density, accounting for the sudden density jump occurring at the phase transition. In this paper we concern ourselves with the extension of this model to take into account the existence of the critical point in the coexistence line.

math-ph↗

arXiv2010

Well posedness of an isothermal diffusive model for binary mixtures of incompressible fluids

We consider a model describing the behavior of a mixture of two incompressible fluids with the same density in isothermal conditions. The model consists of three balance equations: continuity equation, Navier-Stokes equation for the mean velocity of the mixture, and diffusion equation (Cahn-Hilliard equation). We assume that the chemical potential depends upon the velocity of the mixture in such a way that an increase of the velocity improves the miscibility of the mixture. We examine the thermodynamic consistence of the model which leads to the introduction of an additional constitutive force in the motion equation. Then, we prove existence and uniqueness of the solution of the resulting differential problem.

math-ph↗