Title
Positivity-preserving schemes for Euler equations: Sharp and practical CFL conditions
Abstract
When one solves PDEs modelling physical phenomena, it is of great importance to take physical constraints into account. More precisely, numerical schemes have to be designed such that discrete solutions satisfy the same constraints as exact solutions. For instance, the underlying physical assumptions for the Euler equations are the positivity of both density and pressure variables. We consider in this paper an unstructured vertex-based tesselation in R^2. Given a MUSCL finite volume scheme and given a reconstruction method (including a limiting process), the point is to determine whether the overall scheme ensures the positivity. The present work is issued from seminal papers from Perthame and Shu (On positivity preserving finite volume schemes for Euler equations, Numer. Math. 73 (1996) 119-130) and Berthon (Robustness of MUSCL schemes for 2D unstructured meshes, J. Comput. Phys. 218 (2) (2006) 495-509). They proved in different frameworks that under assumptions on the corresponding one-dimensional numerical flux, a suitable CFL condition guarantees that density and pressure remain positive. We first analyse Berthon's method by presenting the ins and outs. We then propose a more general approach adding non geometric degrees of freedom. This approach includes an optimization procedure in order to make the CFL condition explicit and as less restrictive as possible. The reconstruction method is handled independently by means of @t-limiters and of an additional damping parameter. An algorithm is provided in order to specify the adjustments to make in a preexisting code based on a certain numerical flux. Numerical simulations are carried out to prove the accuracy of the method and its ability to deal with low densities and pressures.
Year
DOI
Venue
2013
10.1016/j.jcp.2012.09.040
J. Comput. Physics
Keywords
Field
DocType
physical phenomenon,cfl condition,underlying physical assumption,euler equation,reconstruction method,physical constraint,practical cfl condition,positivity-preserving scheme,certain numerical flux,numerical scheme,corresponding one-dimensional numerical flux,numerical simulation,euler equations
Mathematical optimization,Polygon mesh,Vertex (geometry),Courant–Friedrichs–Lewy condition,Mathematical analysis,Robustness (computer science),MUSCL scheme,Euler equations,Flux limiter,Finite volume method,Mathematics
Journal
Volume
ISSN
Citations 
234,
0021-9991
0
PageRank 
References 
Authors
0.34
9
4
Name
Order
Citations
PageRank
C. Calgaro100.34
E. Creusé2184.59
T. Goudon3162.30
Y. Penel400.34