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Finite element discretization of Darcy's equations with pressure dependent porosity

Vivette Girault, François Murat, Abner Salgado (2010)

ESAIM: Mathematical Modelling and Numerical Analysis

We consider the flow of a viscous incompressible fluid through a rigid homogeneous porous medium. The permeability of the medium depends on the pressure, so that the model is nonlinear. We propose a finite element discretization of this problem and, in the case where the dependence on the pressure is bounded from above and below, we prove its convergence to the solution and propose an algorithm to solve the discrete system. In the case where the dependence on the pressure is exponential, we propose...

Finite element solution of the fundamental equations of semiconductor devices. II

Miloš Zlámal (2001)

Applications of Mathematics

In part I of the paper (see Zlámal [13]) finite element solutions of the nonstationary semiconductor equations were constructed. Two fully discrete schemes were proposed. One was nonlinear, the other partly linear. In this part of the paper we justify the nonlinear scheme. We consider the case of basic boundary conditions and of constant mobilities and prove that the scheme is unconditionally stable. Further, we show that the approximate solution, extended to the whole time interval as a piecewise...

Finite-dimensional Pullback Attractors for Non-autonomous Newton-Boussinesq Equations in Some Two-dimensional Unbounded Domains

Cung The Anh, Dang Thanh Son (2014)

Bulletin of the Polish Academy of Sciences. Mathematics

We study the existence and long-time behavior of weak solutions to Newton-Boussinesq equations in two-dimensional domains satisfying the Poincaré inequality. We prove the existence of a unique minimal finite-dimensional pullback D σ -attractor for the process associated to the problem with respect to a large class of non-autonomous forcing terms.

Finite-energy sign-changing solutions with dihedral symmetry for the stationary nonlinear Schrödinger equation

Monica Musso, Frank Pacard, Juncheng Wei (2012)

Journal of the European Mathematical Society

We address the problem of the existence of finite energy solitary waves for nonlinear Klein-Gordon or Schrödinger type equations Δ u - u + f ( u ) = 0 in ℝ N , u ∈ H 1 ( ℝ N ) , where N ≥ 2 . Under natural conditions on the nonlinearity f , we prove the existence of 𝑖𝑛𝑓𝑖𝑛𝑖𝑡𝑒𝑙𝑦𝑚𝑎𝑛𝑦𝑛𝑜𝑛𝑟𝑎𝑑𝑖𝑎𝑙𝑠𝑜𝑙𝑢𝑡𝑖𝑜𝑛𝑠 in any dimension N ≥ 2 . Our result complements earlier works of Bartsch and Willem ( N = 4 𝚘𝚛 N ≥ 6 ) and Lorca-Ubilla ( N = 5 ) where solutions invariant under the action of O ( 2 ) × O ( N - 2 ) are constructed. In contrast, the solutions we construct are invariant under the action of D k × O ( N - 2 ) where D k ⊂ O ( 2 ) denotes the dihedral group...

Flensted-Jensen's functions attached to the Landau problem on the hyperbolic disc

Zouhaïr Mouayn (2007)

Applications of Mathematics

We give an explicit expression of a two-parameter family of Flensted-Jensen’s functions Ψ μ , α on a concrete realization of the universal covering group of U ( 1 , 1 ) . We prove that these functions are, up to a phase factor, radial eigenfunctions of the Landau Hamiltonian on the hyperbolic disc with a magnetic field strength proportional to μ , and corresponding to the eigenvalue 4 α ( α - 1 ) .

Fluide idéal incompressible en dimension deux autour d’un obstacle fin

Christophe Lacave (2008/2009)

Séminaire Équations aux dérivées partielles

Nous étudions le comportement asymptotique des fluides incompressibles dans les domaines extérieurs, quand l’obstacle devient de plus en plus fin, tendant vers une courbe. Nous étendons les travaux d’Iftimie, Lopes Filho, Nussenzveig Lopes et Kelliher dans lesquels les auteurs considèrent des obstacles se contractant vers un point. En utilisant des outils de l’analyse complexe, nous détaillerons le cas des fluides idéaux en dimension deux autour d’une courbe. Nous donnerons ensuite, à titre indicatif,...

Fluides incompressibles à densité variable

Raphaël Danchin (2002/2003)

Séminaire Équations aux dérivées partielles

 On généralise aux fluides incompressibles à densité variable un certain nombre de résultats bien connus pour les équations de Navier-Stokes et d’Euler incompressibles.

Fluides incompressibles horizontalement visqueux

Marius Paicu (2003)

Journées équations aux dérivées partielles

Motivé par l'étude des fluides tournants entre deux plaques, nous considérons l'équation tridimensionnelle de Navier-Stokes incompressible avec viscosité verticale nulle. Nous démontrons l'existence locale et l'unicité de la solution dans un espace critique (invariant par le changement d'échelle de l'équation). La solution est globale en temps si la donnée initiale est petite par rapport à la viscosité horizontale. Nous obtenons l'unicité de la solution dans un espace plus grand que l'espace des...

Fluids with anisotropic viscosity

Jean-Yves Chemin, Benoît Desjardins, Isabelle Gallagher, Emmanuel Grenier (2000)

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

Fluids with anisotropic viscosity

Jean-Yves Chemin, Benoît Desjardins, Isabelle Gallagher, Emmanuel Grenier (2010)

ESAIM: Mathematical Modelling and Numerical Analysis

Motivated by rotating fluids, we study incompressible fluids with anisotropic viscosity. We use anisotropic spaces that enable us to prove existence theorems for less regular initial data than usual. In the case of rotating fluids, in the whole space, we prove Strichartz-type anisotropic, dispersive estimates which allow us to prove global wellposedness for fast enough rotation.

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