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Régularité microlocale pour des problèmes aux limites non linéaires

Monique Sable-Tougeron (1986)

Annales de l'institut Fourier

On étudie la régularité microlocale de type Sobolev au voisinage du bord d’un ouvert de R n pour des solutions réelles d’un problème aux limites non linéaire non caractéristique dans la zone à comportement linéaire decrite par J. M. Bony : au delà des chocs et en dessous de l’interaction. Pour ces solutions le front d’onde au bord est bien défini et ne contient pas les points de bord elliptiques au sens de Melrose pour le linéarisé sur la solution, si celle-ci vérifie des conditions aux limites régulières....

Regularity analysis for systems of reaction-diffusion equations

Thierry Goudon, Alexis Vasseur (2010)

Annales scientifiques de l'École Normale Supérieure

This paper is devoted to the study of the regularity of solutions to some systems of reaction–diffusion equations. In particular, we show the global boundedness and regularity of the solutions in one and two dimensions. In addition, we discuss the Hausdorff dimension of the set of singularities in higher dimensions. Our approach is inspired by De Giorgi’s method for elliptic regularity with rough coefficients. The proof uses the specific structure of the system to be considered and is not a mere...

Regularity and Blow up for Active Scalars

A. Kiselev (2010)

Mathematical Modelling of Natural Phenomena

We review some recent results for a class of fluid mechanics equations called active scalars, with fractional dissipation. Our main examples are the surface quasi-geostrophic equation, the Burgers equation, and the Cordoba-Cordoba-Fontelos model. We discuss nonlocal maximum principle methods which allow to prove existence of global regular solutions for the critical dissipation. We also recall what is known about the possibility of finite time blow...

Regularity and optimal control of quasicoupled and coupled heating processes

Jiří Jarušek (1996)

Applications of Mathematics

Sufficient conditions for the stresses in the threedimensional linearized coupled thermoelastic system including viscoelasticity to be continuous and bounded are derived and optimization of heating processes described by quasicoupled or partially linearized coupled thermoelastic systems with constraints on stresses is treated. Due to the consideration of heating regimes being “as nonregular as possible” and because of the well-known lack of results concerning the classical regularity of solutions...

Regularity and uniqueness in quasilinear parabolic systems

Pavel Krejčí, Lucia Panizzi (2011)

Applications of Mathematics

Inspired by a problem in steel metallurgy, we prove the existence, regularity, uniqueness, and continuous data dependence of solutions to a coupled parabolic system in a smooth bounded 3D domain, with nonlinear and nonhomogeneous boundary conditions. The nonlinear coupling takes place in the diffusion coefficient. The proofs are based on anisotropic estimates in tangential and normal directions, and on a refined variant of the Gronwall lemma.

Regularity criterion for 3D Navier-Stokes equations in terms of the direction of the velocity

Alexis Vasseur (2009)

Applications of Mathematics

In this short note we give a link between the regularity of the solution u to the 3D Navier-Stokes equation and the behavior of the direction of the velocity u / | u | . It is shown that the control of Div ( u / | u | ) in a suitable L t p ( L x q ) norm is enough to ensure global regularity. The result is reminiscent of the criterion in terms of the direction of the vorticity, introduced first by Constantin and Fefferman. However, in this case the condition is not on the vorticity but on the velocity itself. The proof, based on very...

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