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Sistemi iperbolici di leggi di conservazione

Alberto Bressan (2000)

Bollettino dell'Unione Matematica Italiana

This survey paper provides a brief introduction to the mathematical theory of hyperbolic systems of conservation laws in one space dimension. After reviewing some basic concepts, we describe the fundamental theorem of Glimm on the global existence of BV solutions. We then outline the more recent results on uniqueness and stability of entropy weak solutions. Finally, some major open problems and research directions are discussed in the last section.

Solution of a linear model of a single-piston pump by means of methods for differential equations in Hilbert spaces

Ivan Straškraba (1986)

Aplikace matematiky

A mathematical model of a fluid flow in a single-piston pump is formulated and solved. Variation of pressure and rate of flow in suction and delivery piping respectively is described by linearized Euler equations for barotropic fluid. A new phenomenon is introduced by a boundary condition with discontinuous coefficient describing function of a valve. The system of Euler equations is converted to a second order equation in the space L 2 ( 0 , l ) where l is length of the pipe. The existence, unicity and stability...

Solutions with vortices of a semi-stiff boundary value problem for the Ginzburg–Landau equation

Leonid Berlyand, Volodymyr Rybalko (2010)

Journal of the European Mathematical Society

We study solutions of the 2D Ginzburg–Landau equation - Δ u + ε - 2 u ( | u | 2 - 1 ) = 0 subject to “semi-stiff” boundary conditions: Dirichlet conditions for the modulus, | u | = 1 , and homogeneous Neumann conditions for the phase. The principal result of this work shows that there are stable solutions of this problem with zeros (vortices), which are located near the boundary and have bounded energy in the limit of small ε . For the Dirichlet boundary condition (“stiff” problem), the existence of stable solutions with vortices, whose energy...

Some decay properties for the damped wave equation on the torus

Nalini Anantharaman, Matthieu Léautaud (2012)

Journées Équations aux dérivées partielles

This article is a proceedings version of the ongoing work [1], and has been the object of a talk of the second author during the Journées “Équations aux Dérivées Partielles” (Biarritz, 2012).We address the decay rates of the energy of the damped wave equation when the damping coefficient b does not satisfy the Geometric Control Condition (GCC). First, we give a link with the controllability of the associated Schrödinger equation. We prove that the observability of the Schrödinger group implies that...

Spatiotemporal Dynamics in a Spatial Plankton System

R. K. Upadhyay, W. Wang, N. K. Thakur (2010)

Mathematical Modelling of Natural Phenomena

In this paper, we investigate the complex dynamics of a spatial plankton-fish system with Holling type III functional responses. We have carried out the analytical study for both one and two dimensional system in details and found out a condition for diffusive instability of a locally stable equilibrium. Furthermore, we present a theoretical analysis of processes of pattern formation that involves organism distribution and their interaction of spatially...

Stabilité des solitons de l’équation de Landau-Lifshitz à anisotropie planaire

André de Laire, Philippe Gravejat (2014/2015)

Séminaire Laurent Schwartz — EDP et applications

Cet exposé présente plusieurs résultats récents quant à la stabilité des solitons sombres de l’équation de Landau-Lifshitz à anisotropie planaire, en particulier, quant à la stabilité orbitale des trains (bien préparés) de solitons gris [16] et à la stabilité asymptotique de ces mêmes solitons [2].

Stabilité et asymptotique en temps grand de solutions globales des équations de Navier-Stokes

Isabelle Gallagher, Dragoş Iftimie, Fabrice Planchon (2002)

Journées équations aux dérivées partielles

We study a priori global strong solutions of the incompressible Navier-Stokes equations in three space dimensions. We prove that they behave for large times like small solutions, and in particular they decay to zero as time goes to infinity. Using that result, we prove a stability theorem showing that the set of initial data generating global solutions is open.

Stabilité L 1 d’ondes progressives de lois de conservation scalaires

Denis Serre (1998/1999)

Séminaire Équations aux dérivées partielles

A powerfull method has been developped in [2] for the study of L 1 -stability of travelling waves in conservation laws or more generally in equations which display L 1 -contractivity, maximum principle and mass conservation. We recall shortly the general procedure. We also show that it partly applies to the waves of a model of radiating gas. These waves have first been studied by Kawashima and Nishibata [5,6] in a different framework. Therefore, shock fronts for this model are stable under mild perturbations....

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