Displaying 21 – 40 of 108

Showing per page

Boundary conditions on artificial frontiers for incompressible and compressible Navier-Stokes equations

Charles-Henri Bruneau (2010)

ESAIM: Mathematical Modelling and Numerical Analysis

Non reflecting boundary conditions on artificial frontiers of the domain are proposed for both incompressible and compressible Navier-Stokes equations. For incompressible flows, the boundary conditions lead to a well-posed problem, convey properly the vortices without any reflections on the artificial limits and allow to compute turbulent flows at high Reynolds numbers. For compressible flows, the boundary conditions convey properly the vortices without any reflections on the artificial limits...

Comparaison entre modèles d'ondes de surface en dimension 2

Youcef Mammeri (2007)

ESAIM: Mathematical Modelling and Numerical Analysis

Partant du principe de conservation de la masse et du principe fondamental de la dynamique, on retrouve l'équation d'Euler nous permettant de décrire les modèles asymptotiques de propagation d'ondes dans des eaux peu profondes en dimension 1. Pour décrire la propagation des ondes en dimension 2, Kadomtsev et Petviashvili [ 15 (1970) 539] utilisent une perturbation linéaire de l'équation de KdV. Mais cela ne précise pas si les équations ainsi obtenues dérivent de l'équation d'Euler, c'est ce que...

Computational technique for treating the nonlinear Black-Scholes equation with the effect of transaction costs

Hitoshi Imai, Naoyuki Ishimura, Hideo Sakaguchi (2007)

Kybernetika

We deal with numerical computation of the nonlinear partial differential equations (PDEs) of Black–Scholes type which incorporate the effect of transaction costs. Our proposed technique surmounts the difficulty of infinite domains and unbounded values of the solutions. Numerical implementation shows the validity of our scheme.

Convergence Rates of the POD–Greedy Method

Bernard Haasdonk (2013)

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

Iterative approximation algorithms are successfully applied in parametric approximation tasks. In particular, reduced basis methods make use of the so-called Greedy algorithm for approximating solution sets of parametrized partial differential equations. Recently, a priori convergence rate statements for this algorithm have been given (Buffa et al. 2009, Binev et al. 2010). The goal of the current study is the extension to time-dependent problems, which are typically approximated using the POD–Greedy...

Convergent algorithms suitable for the solution of the semiconductor device equations

Miroslav Pospíšek (1995)

Applications of Mathematics

In this paper, two algorithms are proposed to solve systems of algebraic equations generated by a discretization procedure of the weak formulation of boundary value problems for systems of nonlinear elliptic equations. The first algorithm, Newton-CG-MG, is suitable for systems with gradient mappings, while the second, Newton-CE-MG, can be applied to more general systems. Convergence theorems are proved and application to the semiconductor device modelling is described.

Curved triangular finite C m -elements

Alexander Ženíšek (1978)

Aplikace matematiky

Curved triangular C m -elements which can be pieced together with the generalized Bell’s C m -elements are constructed. They are applied to solving the Dirichlet problem of an elliptic equation of the order 2 ( m + 1 ) in a domain with a smooth boundary by the finite element method. The effect of numerical integration is studied, sufficient conditions for the existence and uniqueness of the approximate solution are presented and the rate of convergence is estimated. The rate of convergence is the same as in the...

Div-curl lemma revisited: Applications in electromagnetism

Marián Slodička, Ján Jr. Buša (2010)

Kybernetika

Two new time-dependent versions of div-curl results in a bounded domain Ω 3 are presented. We study a limit of the product v k w k , where the sequences v k and w k belong to Ł 2 ( Ω ) . In Theorem 2.1 we assume that × v k is bounded in the L p -norm and · w k is controlled in the L r -norm. In Theorem 2.2 we suppose that × w k is bounded in the L p -norm and · w k is controlled in the L r -norm. The time derivative of w k is bounded in both cases in the norm of - 1 ( Ω ) . The convergence (in the sense of distributions) of v k w k to the product v w of weak limits...

Currently displaying 21 – 40 of 108