Flows for the stochastic Navier-Stokes equation.
Flows generated by symmetric functions of the eigenvalues of the Hessian
Flows of heat and time moving boundary
Fluid flow in macromolecular systems and related perturbation problems
Fluide idéal incompressible en dimension deux autour d’un obstacle fin
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
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
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...
Fluides légèrement compressibles et limite incompressible
Fluids with anisotropic viscosity
Fluids with anisotropic viscosity
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.
Fluid-structure interaction : analysis of a 3-D compressible model
Flutter panel equation in non cylindrical domain.
Flux terms and Robin boundary conditions as limit of reactions and potentials concentrating at the boundary.
Flux-upwind stabilization of the discontinuous Petrov–Galerkin formulation with Lagrange multipliers for advection-diffusion problems
In this work we consider the dual-primal Discontinuous Petrov–Galerkin (DPG) method for the advection-diffusion model problem. Since in the DPG method both mixed internal variables are discontinuous, a static condensation procedure can be carried out, leading to a single-field nonconforming discretization scheme. For this latter formulation, we propose a flux-upwind stabilization technique to deal with the advection-dominated case. The resulting scheme is conservative and satisfies a discrete maximum...
Flux-upwind stabilization of the discontinuous Petrov–Galerkin formulation with Lagrange multipliers for advection-diffusion problems
In this work we consider the dual-primal Discontinuous Petrov–Galerkin (DPG) method for the advection-diffusion model problem. Since in the DPG method both mixed internal variables are discontinuous, a static condensation procedure can be carried out, leading to a single-field nonconforming discretization scheme. For this latter formulation, we propose a flux-upwind stabilization technique to deal with the advection-dominated case. The resulting scheme is conservative and satisfies a discrete...
Focusing and absorption of nonlinear oscillations
Focusing of a pulse with arbitrary phase shift for a nonlinear wave equation
We consider a system of two linear conservative wave equations, with a nonlinear coupling, in space dimension three. Spherical pulse like initial data cause focusing at the origin in the limit of short wavelength. Because the equations are conservative, the caustic crossing is not trivial, and we analyze it for particular initial data. It turns out that the phase shift between the incoming wave (before the focus) and the outgoing wave (past the focus) behaves like , where stands for the wavelength....
Focusing of spherical nonlinear pulses in R1+3. II. Nonlinear caustic.
We study spherical pulse like families of solutions to semilinear wave equattions in space time of dimension 1+3 as the pulses focus at a point and emerge outgoing. We emphasize the scales for which the incoming and outgoing waves behave linearly but the nonlinearity has a strong effect at the focus. The focus crossing is described by a scattering operator for the semilinear equation, which broadens the pulses. The relative errors in our approximate solutions are small in the L∞ norm.
Fokker-Planck equation in bounded domain
We study the existence and the uniqueness of a solution to the linear Fokker-Planck equation in a bounded domain of when is a “confinement” vector field. This field acting for instance like the inverse of the distance to the boundary. An illustration of the obtained results is given within the framework of fluid mechanics and polymer flows.
Foliation of phase space for the cubic non-linear Schrödinger equation