Statistical study of Navier-Stokes equations, I
Statistical study of Navier-Stokes equations, II
Statistically stationary solutions to the 3-D Navier-Stokes equation do not show singularities.
Steady compressible Navier-Stokes-Fourier system in two space dimensions
We study steady flow of a compressible heat conducting viscous fluid in a bounded two-dimensional domain, described by the Navier-Stokes-Fourier system. We assume that the pressure is given by the constitutive equation , where is the density and is the temperature. For , we prove existence of a weak solution to these equations without any assumption on the smallness of the data. The proof uses special approximation of the original problem, which guarantees the pointwise boundedness of the...
Steady compressible Oseen flow with slip boundary conditions
We prove the existence of solution in the class H²(Ω) × H¹(Ω) to the steady compressible Oseen system with slip boundary conditions in a two dimensional, convex domain with boundary of class . The method is to regularize a weak solution obtained via the Galerkin method. The problem of regularization is reduced to the problem of solvability of a certain transport equation by application of the Helmholtz decomposition. The method works under an additional assumption on the geometry of the boundary....
Steady-state bifurcations of the three-dimensional Kolmogorov problem.
Stochastic Lagrangian method for downscaling problems in computational fluid dynamics
This work aims at introducing modelling, theoretical and numerical studies related to a new downscaling technique applied to computational fluid dynamics. Our method consists in building a local model, forced by large scale information computed thanks to a classical numerical weather predictor. The local model, compatible with the Navier-Stokes equations, is used for the small scale computation (downscaling) of the considered fluid. It is inspired by Pope's works on turbulence, and consists in...
Stokes and Navier–Stokes equations with nonhomogeneous boundary conditions
Stokes equations in asymptotically flat layers
We study the generalized Stokes resolvent equations in asymptotically flat layers, which can be considered as compact perturbations of an infinite (flat) layer . Besides standard non-slip boundary conditions, we consider a mixture of slip and non-slip boundary conditions on the upper and lower boundary, respectively. We discuss the results on unique solvability of the generalized Stokes resolvent equations as well as the existence of a bounded -calculus for the associated Stokes operator and some...
Stopping a viscous fluid by a feedback dissipative field: II. The stationary Navier-Stokes problem
We consider a planar stationary flow of an incompressible viscous fluid in a semi-infinite strip governed by the Navier-Stokes system with a feed-back body forces field which depends on the velocity field. Since the presence of this type of non-linear terms is not standard in the fluid mechanics literature, we start by establishing some results about existence and uniqueness of weak solutions. Then, we prove how this fluid can be stopped at a finite distance of the semi-infinite strip entrance by...
Strong Lp-Solutions of the Navier-Stokes Equation in Rm, with Applications to Weak Solutions.
Strong solutions of the steady nonlinear Navier-Stokes system in domains with exits to infinity
Structural evolution of the Taylor vortices
Structural Evolution of the Taylor Vortices
We classify in this article the structure and its transitions/evolution of the Taylor vortices with perturbations in one of the following categories: a) the Hamiltonian vector fields, b) the divergence-free vector fields, and c). the solutions of the Navier-Stokes equations on the two-dimensional torus. This is part of a project oriented toward to developing a geometric theory of incompressible fluid flows in the physical spaces.
Su un problema esterno relativo alle equazioni di Navier-Stokes
Sur la propagation de quasi-singularités
Sur la Régularité des Solutions faibles des Equations de Navier-Stokes isentropiques en dimension deux
Sur la théorie globale des équations de Navier-Stokes compressible
Le but de cet article est de présenter quelques résultats mathématiques plus ou moins récents sur la théorie de l’existence globale en temps (solutions faibles et solutions fortes) pour les équations de Navier-Stokes compressibles en dimension supérieure ou égale à deux sans aucune hypothèse de symétrie sur le domaine et sans aucune hypothèse sur la taille des données initiales.
Sur le temps de vie de la turbulence bidimensionnelle
On sait que toutes les solutions de l’équation de Navier-Stokes dans dont le tourbillon est intégrable convergent lorsque vers un écoulement autosimilaire appelé tourbillon d’Oseen. Dans cet article, nous donnons une estimation du temps nécessaire à la solution pour atteindre un voisinage du tourbillon d’Oseen à partir d’une donnée initiale arbitraire, mais bien localisée en espace. Nous obtenons ainsi une borne supérieure sur le temps de vie de la turbulence bidimensionnelle libre, en fonction...
Sur l’équation de Prandtl
L’objet de cette note est le problème de Cauchy pour l’équation de Prandtl, dans des espaces de régularité Sobolev. Nous discutons de façon synthétique des résultats récents [4], établissant le caractère fortement linéairement mal posé de ce problème.