• Medientyp: Sonstige Veröffentlichung; E-Artikel
  • Titel: Quasi-optimality of a pressure-robust nonconforming finite element method for the Stokes-Problem
  • Beteiligte: Merdon, Christian [Verfasser:in]; Neumann, Felix [Verfasser:in]; Neilan, Michael [Verfasser:in]; Linke, Alexander [Verfasser:in]
  • Erschienen: Weierstrass Institute for Applied Analysis and Stochastics publication server, 2018
  • Sprache: Englisch
  • DOI: https://doi.org/10.1090/mcom/3344
  • ISSN: 0025-5718
  • Schlagwörter: article ; incompressible Stokes equations -- mixed finite element methods -- nonconforming discretizations -- pressure-robustness -- a-priori error estimates -- Helmholtz projector
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  • Beschreibung: Nearly all classical inf-sup stable mixed finite element methods for the incompressible Stokes equations are not pressure-robust, i.e., the velocity error is dependent on the pressure. However, recent results show that pressure-robustness can be recovered by a nonstandard discretization of the right-hand side alone. This variational crime introduces a consistency error in the method which can be estimated in a straightforward manner provided that the exact velocity solution is sufficiently smooth. The purpose of this paper is to analyze the pressure-robust scheme with low regularity. The numerical analysis applies divergence-free $H^1$-conforming Stokes finite element methods as a theoretical tool. As an example, pressure-robust velocity and pressure a priori error estimates will be presented for the (first-order) nonconforming Crouzeix–Raviart element. A key feature in the analysis is the dependence of the errors on the Helmholtz projector of the right-hand side data, and not on the entire data term. Numerical examples illustrate the theoretical results.