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Finite element approximation of a Stefan problem with degenerate Joule heating

John W. Barrett, Robert Nürnberg (2004)

ESAIM: Mathematical Modelling and Numerical Analysis - Modélisation Mathématique et Analyse Numérique

We consider a fully practical finite element approximation of the following degenerate system ∂ ∂ t ρ ( u ) - ∇ . ( α ( u ) ∇ u ) ∋ σ ( u ) | ∇ φ | 2 , ∇ . ( σ ( u ) ∇ φ ) = 0 subject to an initial condition on the temperature, u , and boundary conditions on both u and the electric potential, φ . In the above ρ ( u ) is the enthalpy incorporating the latent heat of melting, α ( u ) > 0 is the temperature dependent heat conductivity, and σ ( u ) ≥ 0 is the electrical conductivity. The latter is zero in the frozen zone, u ≤ 0 , which gives rise to the degeneracy in this Stefan system. In addition to showing stability...

Finite element approximation of a Stefan problem with degenerate Joule heating

John W. Barrett, Robert Nürnberg (2010)

ESAIM: Mathematical Modelling and Numerical Analysis

We consider a fully practical finite element approximation of the following degenerate system ∂ ∂ t ρ ( u ) - ∇ . ( α ( u ) ∇ u ) ∋ σ ( u ) | ∇ φ | 2 , ∇ . ( σ ( u ) ∇ φ ) = 0 subject to an initial condition on the temperature, u, and boundary conditions on both u and the electric potential, ϕ. In the above p(u) is the enthalpy incorporating the latent heat of melting, α(u) > 0 is the temperature dependent heat conductivity, and σ(u) > 0 is the electrical conductivity. The latter is zero in the frozen zone, u ≤ 0, which gives rise to the degeneracy in this Stefan...

Finite element solution of a stationary heat conduction equation with the radiation boundary condition

Zdeněk Milka (1993)

Applications of Mathematics

In this paper we present a weak formulation of a two-dimensional stationary heat conduction problem with the radiation boundary condition. The problem can be described by an operator which is monotone on the convex set of admissible functions. The relation between classical and weak solutions as well as the convergence of the finite element method to the weak solution in the norm of the Sobolev space H 1 ( Ω ) are examined.

Flame Propagation through Large-Scale Vortical Flows: Effect of Equivalence Ratio

L. Kagan, G. Sivashinsky (2010)

Mathematical Modelling of Natural Phenomena

The present work is a continuation of previous studies of premixed gas flames spreading through a space-periodic array of large-scale vorticities, and is motivated by the experimentally known phenomenon of flame extinction by turbulence. The prior work dealt with the strongly non-stoichiometric limit where the reaction rate is controlled by a single (deficient) reactant. In the present study the discussion is extended over a physically more realistic formulation based on a bimolecular reaction...

Fluid-dynamic equations for reacting gas mixtures

Marzia Bisi, Maria Groppi, Giampiero Spiga (2005)

Applications of Mathematics

Starting from the Grad 13-moment equations for a bimolecular chemical reaction, Navier-Stokes-type equations are derived by asymptotic procedure in the limit of small mean paths. Two physical situations of slow and fast reactions, with their different hydrodynamic variables and conservation equations, are considered separately, yielding different limiting results.

Free boundary regularity in Stefan type problems

Ioannis Athanasopoulos (2004)

Atti della Accademia Nazionale dei Lincei. Classe di Scienze Fisiche, Matematiche e Naturali. Rendiconti Lincei. Matematica e Applicazioni

Regularity results of free boundaries for Stefan type problems are discussed. The influence that curvature may have on the behavior of the free boundary is studied and various open problems are also mentioned.

General and physically privileged solutions to certain symmetric systems of linear P.D.E.s with tensor functionals as unknowns

Adriano Montanaro, Diego Pigozzi (2000)

Atti della Accademia Nazionale dei Lincei. Classe di Scienze Fisiche, Matematiche e Naturali. Rendiconti Lincei. Matematica e Applicazioni

We characterize the general solutions to certain symmetric systems of linear partial differential equations with tensor functionals as unknowns. Then we determine the solutions that are physically meaningful in suitable senses related with the constitutive functionals of two simple thermodynamic bodies with fading memory that are globally equivalent, i.e. roughly speaking that behave in the same way along processes not involving cuts. The domains of the constitutive functionals are nowhere dense...

Global existence of strong solutions to the one-dimensional full model for phase transitions in thermoviscoelastic materials

Elisabetta Rocca, Riccarda Rossi (2008)

Applications of Mathematics

This paper is devoted to the analysis of a one-dimensional model for phase transition phenomena in thermoviscoelastic materials. The corresponding parabolic-hyperbolic PDE system features a strongly nonlinear internal energy balance equation, governing the evolution of the absolute temperature ϑ , an evolution equation for the phase change parameter χ , including constraints on the phase variable, and a hyperbolic stress-strain relation for the displacement variable 𝐮 . The main novelty of the model...

Global solution to a generalized nonisothermal Ginzburg-Landau system

Nesrine Fterich (2010)

Applications of Mathematics

The article deals with a nonlinear generalized Ginzburg-Landau (Allen-Cahn) system of PDEs accounting for nonisothermal phase transition phenomena which was recently derived by A. Miranville and G. Schimperna: Nonisothermal phase separation based on a microforce balance, Discrete Contin. Dyn. Syst., Ser. B, 5 (2005), 753–768. The existence of solutions to a related Neumann-Robin problem is established in an N ≤ 3 -dimensional space setting. A fixed point procedure guarantees the existence of solutions...

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