Communications on Applied Mathematics and Computation ›› 2023, Vol. 5 ›› Issue (2): 573-595.doi: 10.1007/s42967-020-00086-2

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Analysis of the SBP-SAT Stabilization for Finite Element Methods Part II: Entropy Stability

R. Abgrall1, J. Nordström2,3, P. Öffner1, S. Tokareva4   

  1. 1 Institute of Mathematics, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland;
    2 Department of Mathematics, Computational Mathematics, Linköping University, 581 83 Linköping, Sweden;
    3 Department of Mathematics and Applied Mathematics, University of Johannesburg, Auckland Park, P. O. Box 524, Johannesburg 2006, South Africa;
    4 Theoretical Division, Applied Mathematics and Plasma Physics Group(T-5), Los Alamos National Laboratory, Los Alamos, NM 87545, USA
  • Received:2019-12-18 Revised:2020-06-08 Online:2023-06-20 Published:2023-05-26
  • Contact: P. Öffner philipp.oeffner@math.uzh.ch E-mail:philipp.oeffner@math.uzh.ch
  • Supported by:
    P.Öffner has been funded by the SNF Grant (Number 200021_175784) and by the UZH Postdoc grant. This research was initiated by a first visit of JN at UZH, and really started during ST postdoc at UZH. This postdoc was funded by an SNF Grant 200021_153604. The Los Alamos unlimited release number is LA-UR-19-32411.

Abstract: In the hyperbolic research community, there exists the strong belief that a continuous Galerkin scheme is notoriously unstable and additional stabilization terms have to be added to guarantee stability. In the first part of the series[6], the application of simultaneous approximation terms for linear problems is investigated where the boundary conditions are imposed weakly. By applying this technique, the authors demonstrate that a pure continuous Galerkin scheme is indeed linearly stable if the boundary conditions are imposed in the correct way. In this work, we extend this investigation to the nonlinear case and focus on entropy conservation. By switching to entropy variables, we provide an estimation of the boundary operators also for nonlinear problems, that guarantee conservation. In numerical simulations, we verify our theoretical analysis.

Key words: Continuous Galerkin, Entropy stability, Simultaneous approximation terms, Initial-boundary value problem, Hyperbolic conservation laws

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