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Cell centered Galerkin methods for diffusive problems

Daniele A. Di Pietro (2012)

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

In this work we introduce a new class of lowest order methods for diffusive problems on general meshes with only one unknown per element. The underlying idea is to construct an incomplete piecewise affine polynomial space with optimal approximation properties starting from values at cell centers. To do so we borrow ideas from multi-point finite volume methods, although we use them in a rather different context. The incomplete polynomial space replaces classical complete polynomial spaces in discrete...

Cell centered Galerkin methods for diffusive problems

Daniele A. Di Pietro (2011)

ESAIM: Mathematical Modelling and Numerical Analysis

In this work we introduce a new class of lowest order methods for diffusive problems on general meshes with only one unknown per element. The underlying idea is to construct an incomplete piecewise affine polynomial space with optimal approximation properties starting from values at cell centers. To do so we borrow ideas from multi-point finite volume methods, although we use them in a rather different context. The incomplete polynomial space replaces classical complete polynomial spaces...

Chute stationnaire d’un solide dans un fluide visqueux incompressible au-dessus d’un plan incliné. Partie 2

M. Hillairet (2007)

Annales de la faculté des sciences de Toulouse Mathématiques

Nous montrons dans cette étude l’existence de configurations stationnaires où une bille tombe le long d’un plan incliné sans le toucher. Nous donnons également des propriétés qualitatives de ces configurations. En particulier, nous nous intéressons à l’orientation du plan par rapport à la verticale quand la masse de la bille est proche de celle d’un volume équivalent de liquide i.e., quand l’écoulement autour de la bille est lent.

Computation of the drag force on a sphere close to a wall

David Gérard-Varet, Matthieu Hillairet (2012)

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

We consider the effect of surface roughness on solid-solid contact in a Stokes flow. Various models for the roughness are considered, and a unified methodology is given to derive the corresponding asymptotics of the drag force in the close-contact limit. In this way, we recover and clarify the various expressions that can be found in previous studies.

Computation of the drag force on a sphere close to a wall

David Gérard-Varet, Matthieu Hillairet (2012)

ESAIM: Mathematical Modelling and Numerical Analysis

We consider the effect of surface roughness on solid-solid contact in a Stokes flow. Various models for the roughness are considered, and a unified methodology is given to derive the corresponding asymptotics of the drag force in the close-contact limit. In this way, we recover and clarify the various expressions that can be found in previous studies.

Computation of the drag force on a sphere close to a wall

David Gérard-Varet, Matthieu Hillairet (2012)

ESAIM: Mathematical Modelling and Numerical Analysis

We consider the effect of surface roughness on solid-solid contact in a Stokes flow. Various models for the roughness are considered, and a unified methodology is given to derive the corresponding asymptotics of the drag force in the close-contact limit. In this way, we recover and clarify the various expressions that can be found in previous studies.

Conditions implying regularity of the three dimensional Navier-Stokes equation

Stephen Montgomery-Smith (2005)

Applications of Mathematics

We obtain logarithmic improvements for conditions for regularity of the Navier-Stokes equation, similar to those of Prodi-Serrin or Beale-Kato-Majda. Some of the proofs make use of a stochastic approach involving Feynman-Kac-like inequalities. As part of our methods, we give a different approach to a priori estimates of Foiaş, Guillopé and Temam.

Conditions of Prodi-Serrin's type for local regularity of suitable weak solutions to the Navier-Stokes equations

Zdeněk Skalák (2002)

Commentationes Mathematicae Universitatis Carolinae

In the context of suitable weak solutions to the Navier-Stokes equations we present local conditions of Prodi-Serrin’s type on velocity 𝐯 and pressure p under which ( 𝐱 0 , t 0 ) Ω × ( 0 , T ) is a regular point of 𝐯 . The conditions are imposed exclusively on the outside of a sufficiently narrow space-time paraboloid with the vertex ( 𝐱 0 , t 0 ) and the axis parallel with the t -axis.

Continuous dependence of 2D large scale primitive equations on the boundary conditions in oceanic dynamics

Yuanfei Li, Shengzhong Xiao (2022)

Applications of Mathematics

In this paper, we consider an initial boundary value problem for the two-dimensional primitive equations of large scale oceanic dynamics. Assuming that the depth of the ocean is a positive constant, we establish rigorous a priori bounds of the solution to problem. With the aid of these a priori bounds, the continuous dependence of the solution on changes in the boundary terms is obtained.

Controllability of three-dimensional Navier–Stokes equations and applications

Armen Shirikyan (2005/2006)

Séminaire Équations aux dérivées partielles

We formulate two results on controllability properties of the 3D Navier–Stokes (NS) system. They concern the approximate controllability and exact controllability in finite-dimensional projections of the problem in question. As a consequence, we obtain the existence of a strong solution of the Cauchy problem for the 3D NS system with an arbitrary initial function and a large class of right-hand sides. We also discuss some qualitative properties of admissible weak solutions for randomly forced NS...

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