Peer-Reviewed Journal Details
Mandatory Fields
Kopteva N.
2020
January
Journal Of Computational And Applied Mathematics
How accurate are finite elements on anisotropic triangulations in the maximum norm?
Published
1 ()
Optional Fields
Anisotropic diffusion Anisotropic triangulation Lagrange finite elements Layer solutions Maximum norm
364
© 2019 Elsevier B.V. In Kopteva (2014) a counterexample of an anisotropic triangulation was given on which the exact solution has a second-order error of linear interpolation, while the computed solution obtained using linear finite elements is only first-order pointwise accurate. This example was given in the context of a singularly perturbed reaction¿diffusion equation. In this paper, we present further examples of unanticipated pointwise convergence behaviour of Lagrange finite elements on anisotropic triangulations. In particular, we show that linear finite elements may exhibit lower than expected orders of convergence for the Laplace equation, as well as for certain singular equations, and their accuracy depends not only on the linear interpolation error, but also on the mesh topology. Furthermore, we demonstrate that pointwise convergence rates which are worse than one might expect are also observed when higher-order finite elements are employed on anisotropic meshes. A theoretical justification will be given for some of the observed numerical phenomena.
0377-0427
10.1016/j.cam.2019.06.032
Grant Details