Auteurs : Burman, Erik (Auteur de la Conférence)
CIRM (Editeur )
Résumé :
Recently there has been a surge in interest in cut, or unfitted, finite element methods. In this class of methods typically the computational mesh is independent of the geometry. Interfaces and boundaries are allowed to cut through the mesh in a very general fashion. Constraints on the boundaries such as boundary or transmission conditions are typically imposed weakly using Nitsche's method. In this talk we will discuss how these ideas can be combined in a fruitful way with the idea of hybridization, where additional degrees of freedom are added on the interfaces to further improve the decoupling of the systems, allowing for static condensation of interior unknowns. In the first part of the talk we will discuss how hybridization can be combined with the classical cut finite element method, using standard H1 -conforming finite elements in each subdomain, leading to a robust method allowing for the integration of polytopal geometries, where the subdomains are independent of the underlying mesh. This leads to a framework where it is easy to integrate multiscale features such as strongly varying coefficients, or multidimensional coupling, as in flow in fractured domains. Some examples of such applications will be given. In the second part of the talk we will focus on the Hybridized High Order Method (HHO) and show how cut techniques can be introduced in this context. The HHO is a recently introduced nonconforming method that allows for arbitrary order discretization of diffusive problems on polytopal meshes. HHO methods have hybrid unknowns, made of polynomials in the mesh elements and on the faces, without any continuity requirement. They rely on high-order local reconstructions, which are used to build consistent Galerkin contributions and appropriate stabilization terms designed to preserve the high-order approximation properties of the local reconstructions. Here we will show how cut element techniques can be introduced as a tool for the handling of (possibly curved) interfaces or boundaries that are allowed to cut through the polytopal mesh. In this context the cut element method plays the role of a local interface model, where the associated degrees of freedom are eliminated in the static condensation step. Issues of robustness and accuracy will be discussed and illustrated by some numerical examples.
Codes MSC :
65N30
- Finite elements, Rayleigh-Ritz and Galerkin methods, finite methods (BVP of PDE)
34A38
- Hybrid systems
Ressources complémentaires :
https://imag.umontpellier.fr/~di-pietro/poems2019/erik_burman.pdf
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Informations sur la Rencontre
Nom de la rencontre : POEMs - POlytopal Element Methods in Mathematics and Engineering Organisateurs de la rencontre : Antonietti, Paola ; Beirão da Veiga, Lourenço ; Di Pietro, Daniele ; Droniou, Jérôme ; Krell, Stella Dates : 29/04/2019 - 03/05/2019
Année de la rencontre : 2019
URL Congrès : https://conferences.cirm-math.fr/1954.html
DOI : 10.24350/CIRM.V.19528803
Citer cette vidéo:
Burman, Erik (2019). Combining cut element methods and hybridization. CIRM. Audiovisual resource. doi:10.24350/CIRM.V.19528803
URI : http://dx.doi.org/10.24350/CIRM.V.19528803
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Voir aussi
Bibliographie
- Girault, V. & Glowinski, R. Japan J. Indust. Appl. Math. (1995) - https://doi.org/10.1007/BF03167240
- Silvia Bertoluzza, Mourad Ismail, Bertrand Maury. The Fat Boundary Method: Semi-Discrete Scheme and Some Numerical Experiments. DOMAIN DECOMPOSITION METHODS IN SCIENCE AND ENGINEERING, springer, pp.513, 2005, Lecture Notes in Computational Science and Engineering. - https://hal.archives-ouvertes.fr/hal-00666064
- HASLINGER, Jaroslav et RENARD, Yves. A new fictitious domain approach inspired by the extended finite element method. SIAM Journal on Numerical Analysis, 2009, vol. 47, no 2, p. 1474-1499. - https://epubs.siam.org/doi/pdf/10.1137/070704435
- BARRETT, John W. et ELLIOTT, Charles M. Fitted and unfitted finite-element methods for elliptic equations with smooth interfaces. IMA journal of numerical analysis, 1987, vol. 7, no 3, p. 283-300. - https://doi.org/10.1093/imanum/7.3.283
- Anita Hansbo, Peter Hansbo. An unfitted finite element method, based on Nitsche's method, for elliptic interface problems. Computer Methods in Applied Mechanics and Engineering, Elsevier, 2002, 191 (47-48), pp. 5537-5552. - https://doi.org/10.1016/S0045-7825(02)00524-8
- OLSHANSKII, Maxim A., REUSKEN, Arnold, et GRANDE, Jörg. A finite element method for elliptic equations on surfaces. SIAM journal on numerical analysis, 2009, vol. 47, no 5, p. 3339-3358. - https://doi.org/10.1137/080717602
- BURMAN, Erik. Ghost penalty. Comptes Rendus Mathematique, 2010, vol. 348, no 21-22, p. 1217-1220. - https://doi.org/10.1016/j.crma.2010.10.006doi.org/10.1016/j.crma.2010.10.006
- LARSON, Mats G. et ZAHEDI, Sara. Stabilization of high order cut finite element methods on surfaces. arXiv preprint arXiv:1710.03343, 2017. - https://arxiv.org/abs/1710.03343
- Daniele Di Pietro, Alexandre Ern. Equilibrated tractions for the Hybrid High-Order method. Comptes Rendus Mathématique, Elsevier Masson, 2015, 353 (3), pp.279--282. - https://doi.org/10.1016/j.crma.2014.12.009
- JOHANSSON, August et LARSON, Mats G. A high order discontinuous Galerkin Nitsche method for elliptic problems with fictitious boundary. Numerische Mathematik, 2013, vol. 123, no 4, p. 607-628. - https://doi.org/10.1007/s00211-012-0497-1IS
- BASTIAN, Peter et ENGWER, Christian. An unfitted finite element method using discontinuous Galerkin. International journal for numerical methods in engineering, 2009, vol. 79, no 12, p. 1557-1576. - https://doi.org/10.1002/nme.2631ISTE
- MASSJUNG, Ralf. An unfitted discontinuous Galerkin method applied to elliptic interface problems. SIAM Journal on Numerical Analysis, 2012, vol. 50, no 6, p. 3134-3162. - https://doi.org/10.1137/090763093
- GÜRKAN, Ceren et MASSING, André. A stabilized cut discontinuous Galerkin framework for elliptic boundary value and interface problems. Computer Methods in Applied Mechanics and Engineering, 2019, vol. 348, p. 466-499. - https://arxiv.org/abs/1803.06635
- CANGIANI, Andrea, GEORGOULIS, Emmanuil, et SABAWI, Younis. Adaptive discontinuous Galerkin methods for elliptic interface problems. Mathematics of Computation, 2018, vol. 87, no 314, p. 2675-2707. - https://doi.org/10.1090/mcom/3322
- COCKBURN, Bernardo, QIU, Weifeng, et SOLANO, Manuel. A priori error analysis for HDG methods using extensions from subdomains to achieve boundary conformity. Mathematics of Computation, 2014, vol. 83, no 286, p. 665-699. - https://doi.org/10.1090/S0025-5718-2013-02747-0
- GÜRKAN, Ceren, SALA-LARDIES, Esther, KRONBICHLER, Martin, et al. eXtended hybridizable discontinuous Galerkin (X-HDG) for void and bimaterial problems. In : Advances in Discretization Methods. Springer, Cham, 2016. p. 103-122. - https://doi.org/10.1007/978-3-319-41246-7_5
- Anita Hansbo, Peter Hansbo. An unfitted finite element method, based on Nitsche's method, for elliptic interface problems. Computer Methods in Applied Mechanics and Engineering, Elsevier, 2002, 191 (47-48), pp. 5537-5552. - https://doi.org/10.1016/S0045-7825(02)00524-8
- BURMAN, Erik et ERN, Alexandre. An unfitted Hybrid High-Order method for elliptic interface problems. SIAM Journal on Numerical Analysis, 2018, vol. 56, no 3, p. 1525-1546. - https://doi.org/10.1137/17M1154266
- BURMAN, Erik, GUZMÁN, Johnny, SÁNCHEZ, Manuel A., et al. Robust flux error estimation of Nitsche's method for high contrast interface problems. arXiv preprint arXiv:1602.00603, 2016, vol. 48. - https://arxiv.org/abs/1602.00603
- HUYNH, L. N. T., NGUYEN, N. C., PERAIRE, J., et al. A high‐order hybridizable discontinuous Galerkin method for elliptic interface problems. International Journal for Numerical Methods in Engineering, 2013, vol. 93, no 2, p. 183-200. - https://doi.org/10.1002/nme.4382