A Comparative Study of Iterative Riemann Solvers for the Shallow Water and Euler Equations

Fuente: arXiv
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Autori principali: Moncayo, Carlos Muñoz, de Luna, Manuel Quezada, Ketcheson, David I.
Natura: Preprint
Pubblicazione: 2022
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author Moncayo, Carlos Muñoz
de Luna, Manuel Quezada
Ketcheson, David I.
author_facet Moncayo, Carlos Muñoz
de Luna, Manuel Quezada
Ketcheson, David I.
contents The Riemann problem for first-order hyperbolic systems of partial differential equations is of fundamental importance for both theoretical and numerical purposes. Many approximate solvers have been developed for such systems; exact solution algorithms have received less attention because computation of the exact solution typically requires iterative solution of algebraic equations. Iterative algorithms may be less computationally efficient or might fail to converge in some cases. We investigate the achievable efficiency of robust iterative Riemann solvers for relatively simple systems, focusing on the shallow water and Euler equations. We consider a range of initial guesses and iterative schemes applied to an ensemble of test Riemann problems. For the shallow water equations, we find that Newton's method with a simple modification converges quickly and reliably. For the Euler equations we obtain similar results; however, when the required precision is high, a combination of Ostrowski and Newton iterations converges faster. These solvers are slower than standard approximate solvers like Roe and HLLE, but come within a factor of two in speed. We also provide a preliminary comparison of the accuracy of a finite volume discretization using an exact solver versus standard approximate solvers.
format Preprint
id arxiv_https___arxiv_org_abs_2209_12235
institution arXiv
publishDate 2022
record_format arxiv
spellingShingle A Comparative Study of Iterative Riemann Solvers for the Shallow Water and Euler Equations
Moncayo, Carlos Muñoz
de Luna, Manuel Quezada
Ketcheson, David I.
Numerical Analysis
65M99 (Primary) 76B15, 35Q31, 35Q35 (Secondary)
The Riemann problem for first-order hyperbolic systems of partial differential equations is of fundamental importance for both theoretical and numerical purposes. Many approximate solvers have been developed for such systems; exact solution algorithms have received less attention because computation of the exact solution typically requires iterative solution of algebraic equations. Iterative algorithms may be less computationally efficient or might fail to converge in some cases. We investigate the achievable efficiency of robust iterative Riemann solvers for relatively simple systems, focusing on the shallow water and Euler equations. We consider a range of initial guesses and iterative schemes applied to an ensemble of test Riemann problems. For the shallow water equations, we find that Newton's method with a simple modification converges quickly and reliably. For the Euler equations we obtain similar results; however, when the required precision is high, a combination of Ostrowski and Newton iterations converges faster. These solvers are slower than standard approximate solvers like Roe and HLLE, but come within a factor of two in speed. We also provide a preliminary comparison of the accuracy of a finite volume discretization using an exact solver versus standard approximate solvers.
title A Comparative Study of Iterative Riemann Solvers for the Shallow Water and Euler Equations
topic Numerical Analysis
65M99 (Primary) 76B15, 35Q31, 35Q35 (Secondary)
url https://arxiv.org/abs/2209.12235