$\phi $-FEM for the heat equation: optimal convergence on unfitted meshes in space

Thanks to a finite element method, we solve numerically parabolic partial differential equations on complex domains by avoiding the mesh generation, using a regular background mesh, not fitting the domain and its real boundary exactly. Our technique follows the $\phi $-FEM paradigm, which supposes t...

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Bibliographic Details
Main Authors: Duprez, Michel, Lleras, Vanessa, Lozinski, Alexei, Vuillemot, Killian
Format: Article
Language:English
Published: Académie des sciences 2023-12-01
Series:Comptes Rendus. Mathématique
Online Access:https://comptes-rendus.academie-sciences.fr/mathematique/articles/10.5802/crmath.497/
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Summary:Thanks to a finite element method, we solve numerically parabolic partial differential equations on complex domains by avoiding the mesh generation, using a regular background mesh, not fitting the domain and its real boundary exactly. Our technique follows the $\phi $-FEM paradigm, which supposes that the domain is given by a level-set function. In this paper, we prove a priori error estimates in $l^2(H^1)$ and $l^\infty (L^2)$ norms for an implicit Euler discretization in time. We give numerical illustrations to highlight the performances of $\phi $-FEM, which combines optimal convergence accuracy, easy implementation process and fastness.
ISSN:1778-3569