(SALLE CHANGEE) Schémas de relaxation de Jin et Xin avec correction par mesure de défaut

Jeudi 10 janvier 14:00-15:00 - Frédéric Coquel - CNRS, CMAP (Ecole Polytechnique)

Résumé : We present a class of finite volume methods for approximating entropy weak so-lutions of non-linear hyperbolic PDEs. The main motivation is to resolve discontinuities aswell as Glimm’s scheme, but without the need for solving Riemann problems exactly. Thesharp capture of discontinuities is known to be mandatory in situations where discontinuitiesare sensitive to viscous perturbations while exact Riemann solutions may not be available(typically in phase transition problems). More generally, sharp capture also prevent discreteshock profiles from exhibiting over and undershoots, which is decisive in a many applications(in combustion for instance). We propose to replace exact Riemann solutions by self-similarsolutions conveniently derived from the Xin-Jin’s relaxation framework. In the limit of a van-ishing relaxation time, the relaxation source term exhibits Dirac measures concentrated onthe discontinuities. We show how to handle those so-called defect measures in order to exactlycapture propagating shock solutions while achieving computational efficiencies. The lecturewill essential focus on the convergence analysis in the scalar setting. A special attention ispaid to the consistency of the proposed correction with respect to the entropy condition. Weprove the convergence of the method to the unique Kruvkov’s solution. This is a joint workwith Shi Jin (Madison-Wisconsin Univ.), Jian-Guo Liu (Duke Univ.) and Li Wang (UCLA).

Lieu : IMO, Salle 3L15

(SALLE CHANGEE) Schémas de relaxation de Jin et Xin avec correction par mesure de défaut  Version PDF