A Novel Averaging Technique for Discrete Entropy-Stable Dissipation Operators for Ideal MHD

Abstract

Entropy stable schemes can be constructed with a specific choice of the numerical flux function. First, an entropy conserving flux is constructed. Secondly, an entropy stable dissipation term is added to this flux to guarantee dissipation of the discrete entropy. Present works in the field of entropy stable numerical schemes are concerned with thorough derivations of entropy conservative fluxes for ideal MHD. However, as we show in this work, if the dissipation operator is not constructed in a very specific way, it cannot lead to a generally stable numerical scheme. The two main findings presented in this paper are that the entropy conserving flux of Ismail & Roe can easily break down for certain initial conditions commonly found in astrophysical simulations, and that special care must be taken in the derivation of a discrete dissipation matrix for an entropy stable numerical scheme to be robust. We present a convenient novel averaging procedure to evaluate the entropy Jacobians of the ideal MHD and the compressible Euler equations that yields a discretization with favorable robustness properties.

arXiv comment10 pages, 2 figures, submitted to Journal of Computational Physics

References in corpus (3)

• Kinetic energy preserving and entropy stable finite volume schemes for compressible Euler and Navier-Stokes equations
• Modelling the supernova-driven ISM in different environments
• A Novel High-Order, Entropy Stable, 3D AMR MHD Solver with Guaranteed Positive Pressure

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• Entropy conservative discretization of compressible Euler equations with an arbitrary equation of state
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• A Note on Numerical Fluxes Conserving a Member of Harten's One-Parameter Family of Entropies for the Compressible Euler Equations