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arXiv · 1712.08006

Raviart Thomas Petrov-Galerkin Finite Elements

François Dubois·Isabelle Greff·Charles Pierre
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Abstract

The general theory of Babu\v{s}ka ensures necessary and sufficient conditions for a mixed problem in classical or Petrov-Galerkin form to be well posed in the sense of Hadamard. Moreover, the mixed method of Raviart-Thomas with low-level elements can be interpreted as a finite volume method with a non-local gradient. In this contribution, we propose a variant of type Petrov-Galerkin to ensure a local computation of the gradient at the interfaces of the elements. The in-depth study of stability leads to a specific choice of the test functions. With this choice, we show on the one hand that the mixed Petrov-Galerkin obtained is identical to the finite volumes scheme "volumes finis \`a 4 points" ("VF4") of Faille, Gallo\"uet and Herbin and to the condensation of mass approach developed by Baranger, Maitre and Oudin. On the other hand, we show the stability via an inf-sup condition and finally the convergence with the usual methods of mixed finite elements.

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François Dubois, Isabelle Greff, Charles Pierre. 2017-12-20. Raviart Thomas Petrov-Galerkin Finite Elements. https://doi.org/10.1007/978-3-319-57397-7_27

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