Parallel fully coupled Schwarz preconditioners for saddle point problems.
Persistance de structures géométriques et limite non visqueuse pour les fluides incompressibles en dimension quelconque
Planar flows of incompressible heat-conducting shear-thinning fluids — existence analysis
We study the flow of an incompressible homogeneous fluid whose material coefficients depend on the temperature and the shear-rate. For large class of models we establish the existence of a suitable weak solution for two-dimensional flows of fluid in a bounded domain. The proof relies on the reconstruction of the globally integrable pressure, available due to considered Navier’s slip boundary conditions, and on the so-called -truncation method, used to obtain the strong convergence of the velocity...
Poches de tourbillon singulières dans un fluide faiblement visqueux.
In this paper, we study the singular vortex patches in the two-dimensional incompressible Navier-Stokes equations. We show, in particular, that if the initial vortex patch is C1+s outside a singular set Σ, so the velocity is, for all time, lipschitzian outside the image of Σ through the viscous flow. In addition, the correponding lipschitzian norm is independent of the viscosity. This allows us to prove some results related to the inviscid limit for the geometric structures of the vortex patch.
Poches de tourbillon visqueuses
Point fixe d'une application non contractante.
We study a multilinear fixed-point equation in a closed ball of a Banach space where the application is 1-Lipschitzian: existence, uniqueness, approximations, regularity.
Prediction-correction Legendre spectral scheme for incompressible fluid flow
Prediction-correction legendre spectral scheme for incompressible fluid flow
The initial-boundary value problem of two-dimensional incompressible fluid flow in stream function form is considered. A prediction-correction Legendre spectral scheme is proposed, which is easy to be performed. The numerical solution possesses the accuracy of second-order in time and higher order in space. The numerical experiments show the high accuracy of this approach.
Pressure conditions for the local regularity of solutions of the Navier-Stokes equations.
Probabilistic analysis of singularities for the 3-D Navier-Stokes equations
Probabilistic analysis of singularities for the 3D Navier-Stokes equations
The classical result on singularities for the 3D Navier-Stokes equations says that the -dimensional Hausdorff measure of the set of singular points is zero. For a stochastic version of the equation, new results are proved. For statistically stationary solutions, at any given time , with probability one the set of singular points is empty. The same result is true for a.e. initial condition with respect to a measure related to the stationary solution, and if the noise is sufficiently non degenerate...
Probability & incompressible Navier-Stokes equations: an overview of some recent developments.
Problème de la surface libre de l'équation de Navier-Stokes —Cas stationnaire et cas périodique—
Problème de Stokes et système de Navier-Stokes incompressible à densité variable dans le demi-espace
On s’intéresse à la résolution du système de Navier-Stokes incompressible à densité variable dans le demi-espace en dimension On considère des données initiales à régularité critique. On établit que si la densité initiale est proche d’une constante strictement positive dans et si la vitesse initiale est petite par rapport à la viscosité dans l’espace de Besov homogène alors le système de Navier-Stokes admet une unique solution globale. La démonstration repose sur de nouvelles estimations...
Produits rapides matrice-vecteur en bases d'ondelettes : application à la résolution numérique d'équations aux dérivés partielles
Profile decomposition for solutions of the Navier-Stokes equations
We consider sequences of solutions of the Navier-Stokes equations in , associated with sequences of initial data bounded in . We prove, in the spirit of the work of H.Bahouri and P.Gérard (in the case of the wave equation), that they can be decomposed into a sum of orthogonal profiles, bounded in , up to a remainder term small in ; the method is based on the proof of a similar result for the heat equation, followed by a perturbation–type argument. If is an “admissible” space (in particular ...
Propagation of chaos for the 2D viscous vortex model
We consider a stochastic system of particles, usually called vortices in that setting, approximating the 2D Navier-Stokes equation written in vorticity. Assuming that the initial distribution of the position and circulation of the vortices has finite (partial) entropy and a finite moment of positive order, we show that the empirical measure of the particle system converges in law to the unique (under suitable a priori estimates) solution of the 2D Navier-Stokes equation. We actually prove a slightly...
Properties of time-dependent statistical solutions of the three-dimensional Navier-Stokes equations
This work is devoted to the concept of statistical solution of the Navier-Stokes equations, proposed as a rigorous mathematical object to address the fundamental concept of ensemble average used in the study of the conventional theory of fully developed turbulence. Two types of statistical solutions have been proposed in the 1970’s, one by Foias and Prodi and the other one by Vishik and Fursikov. In this article, a new, intermediate type of statistical solution is introduced and studied. This solution...
Pullback attractors for non-autonomous 2D MHD equations on some unbounded domains
We study the 2D magnetohydrodynamic (MHD) equations for a viscous incompressible resistive fluid, a system with the Navier-Stokes equations for the velocity field coupled with a convection-diffusion equation for the magnetic fields, in an arbitrary (bounded or unbounded) domain satisfying the Poincaré inequality with a large class of non-autonomous external forces. The existence of a weak solution to the problem is proved by using the Galerkin method. We then show the existence of a unique minimal...