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Un modèle asymptotique pour les ondes internes de grande amplitude

Jean-Claude Saut (2009/2010)

Séminaire Équations aux dérivées partielles

On considère dans cet exposé le modèle asymptotique “shallow-water/shallow-water" obtenu dans [3] à partir du système d’Euler à deux couches avec fond plat et toit rigide pour décrire la propagation d’ondes internes de grande amplitude. En dimension d’espace un, ce système est de type hyperbolique et la théorie locale du problème de Cauchy ne pose pas de difficultés majeures, même si d’autres questions (explosion en temps fini, perte d’hyperbolicité) s’avèrent délicates. En dimension deux d’espace...

Un problema di omogeneizzazione bidimensionale

Stefano Mortola, Sergio Steffè (1985)

Atti della Accademia Nazionale dei Lincei. Classe di Scienze Fisiche, Matematiche e Naturali. Rendiconti Lincei. Matematica e Applicazioni

In this note we study the periodic homogenization problem for a particular bidimensional selfadjoint elliptic operator of the second order. Theoretical and numerical considerations allow us to conjecture explicit formulae for the coefficients of the homogenized operator.

Un problema di Riemann-Hilbert non regolare per una coppia di operatori ellittici di ordine 2 ⁢ m .

Mario Tosques (1984)

Atti della Accademia Nazionale dei Lincei. Classe di Scienze Fisiche, Matematiche e Naturali. Rendiconti Lincei. Matematica e Applicazioni

We consider the problem of finding a couple of solutions ( u + , u - ) satisfying the following conditions (4) and (5) for a couple of two uniformly elliptic partial differential operators A + and A - of order 2 ⁢ m in a non regular situation.

Un problème Spectral Issu d'un Couplage Elasto-Acoustique

Mario Durán, Jean-Claude Nédélec (2010)

ESAIM: Mathematical Modelling and Numerical Analysis

We are interested in the theoretical study of a spectral problem arising in a physical situation, namely interactions of fluid-solid type structure. More precisely, we study the existence of solutions for a quadratic eigenvalue problem, which describes the vibrations of a system made up of two elastic bodies, where a slip is allowed on their interface and which surround a cavity full of an inviscid and slightly compressible fluid. The problem shall be treated like a generalized eigenvalue...

Un résultat de convergence d'ordre deux en temps pour l'approximation des équations de Navier–Stokes par une technique de projection incrémentale

Jean-Luc Guermond (2010)

ESAIM: Mathematical Modelling and Numerical Analysis

The Navier–Stokes equations are approximated by means of a fractional step, Chorin–Temam projection method; the time derivative is approximated by a three-level backward finite difference, whereas the approximation in space is performed by a Galerkin technique. It is shown that the proposed scheme yields an error of 𝒪 ( δ t 2 + h l + 1 ) for the velocity in the norm of l2(L2(Ω)d), where l ≥ 1 is the polynomial degree of the velocity approximation. It is also shown that the splitting error of projection schemes based...

Currently displaying 81 – 100 of 355