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  1. 1

    A note on nonlinear KdV-type equations

    Publicação
    por Bedjaoui, Nabil
    Outros Autores: Correia, Joaquim M.C.
    We consider the approximation of the inviscid Burgers equation by nonlinear Korteweg-de Vries (KdV) type equations. It has been conjectured by Brenier and Levy [1] that in some special kind of nonlinear dispersion the behaviour is dissipative, when generally we expect a dispersive behaviour as in the linear case. We provide here a priori estimates enough to establish the first step in a proof of the conjecture above.
    2013 artigo Portugal acesso restrito
  2. 2

    Zero limit of dispersive-dissipative perturbed hyperbolic conservation laws

    Publicação
    por Correia, Joaquim M.C.
    We consider the initial value problem for full nonlinear dissipative-dispersive perturbations of multidimensional scalar hyperbolic conservation laws, say generalized KdV-Burgers equations. And, as the perturbations vanish, we analyse the convergence of solutions for such problem to the classical entropy weak solution of the limit hyperbolic conservation laws. This is a step for the proof of a “vanishing viscosity-capillarity method”. We use the setting of DiPerna’s measure-valued solution uniqueness result. The class of equations under consideration have the form of \pa_t u+div f(u)=\eps div b(u,\grad u)+\del div \pa_(\xi) c(u,\grad u), which include generalized Korteweg-de Vries-Burgers equation (when \xi is a space variable) and Benjamin-Bona-Mahony-Burgers equation (when \xi is the time variable), or that of \pa_t u+div f(u)=\del div c(u,\grad \pa_(\xi)u), which can present unexpected dissipative properties.
    2015 palestra Portugal acesso restrito
  3. 3

    Nonlinear Hyperbolicity

    Publicação
    por Correia, Joaquim
    In this presentation we attempt to stress two points of view on hyperbolic conservation laws: modelization and analytical theory. And, how they are sensitively related. While appliers are concerned with reliability, integrity or failure of solutions, mathematicians are concerned with non uniqueness, selection of physically relevant solutions or entropy criteria. In the modeling process, within simplifications, some “spurious terms” are usually discarded from the equations and so, in order to address uniqueness, a crucial information is lost. We discuss here the relevant dissipative or dispersive effect of some of those small scale terms (zero singular limits).
    2014 palestra Portugal acesso aberto
  4. 4

    Nonlinearly perturbed hyperbolic conservation laws

    Publicação
    por Correia, Joaquim
    In this presentation we attempt to stress two points of view on hyperbolic conservation laws: modelization and analytical theory. And, how they are sensitively related. While appliers are concerned with reliability, integrity or failure of solutions, mathematcians are concerned with non uniqueness, selection of physically relevant solutions or entropy criteria. In the modeling process, within simplifications, some “spurious terms” are usually discarded from the equations and so, in order to address uniqueness, a crucial information is lost. We discuss here the relevant dissipative or dispersive effect of some of those small scale terms (zero singular limits).
    2014 palestra Portugal acesso aberto
  5. 5

    The Hyperbolic Paradigma

    Publicação
    por Correia, Joaquim M. C.
    As nonlinear hyperbolic partial differential equations have non unique global solutions, I am concerned with two, related, issues: what about physical solutions? and when can we use such a type of equations?
    2014 palestra Portugal acesso aberto