A large time-step and well-balanced Lagrange-Projection type scheme for the shallow-water equations

Christophe Chalons (1) , Pierre Kestener (2) , Samuel Kokh (3) , Maxime Stauffert (1)

1 LMV - Laboratoire de Mathématiques de Versailles
2 MDLS - Maison de la Simulation
3 STMF - Service de Thermo-hydraulique et de Mécanique des Fluides

This work focuses on the numerical approximation of the shallow water equations (SWE) using a Lagrange-projection type approach. We propose to extend to this context the recent implicit-explicit schemes developed in [C. Chalons, M. Girardin, and S. Kokh, SIAM J. Sci. Comput., 35(6):a2874–a2902, 2013], [C. Chalons, M. Girardin, and S. Kokh, Commun. Comput. Phys., to appear, 20(1):188–233, 2016] in the framework of compressible flows, with or without stiff source terms. These methods enable the use of time steps that are no longer constrained by the sound velocity thanks to an implicit treatment of the acoustic waves, and maintain accuracy in the subsonic regime thanks to an explicit treatment of the material waves. In the present setting, a particular attention will be also given to the discretization of the non-conservative terms in SWE and more specifically to the wellknown well-balanced property. We prove that the proposed numerical strategy enjoys important non linear stability properties and we illustrate its behaviour past several relevant test cases.

Mots clés: shallow water equations; Lagrange-projection schemes; implicit-explicit schemes; large time steps; well-balanced property

Domaines: Analyse numérique [math.NA]

Christophe Chalons, Pierre Kestener, Samuel Kokh, Maxime Stauffert. A large time-step and well-balanced Lagrange-Projection type scheme for the shallow-water equations. Communications in Mathematical Sciences, 2017, 15 (3), pp.765-788. ⟨10.4310/CMS.2017.v15.n3.a9⟩. ⟨hal-01297043v2⟩