The pressure-wired Stokes element: a mesh-robust version of the Scott-Vogelius element

Fuente: arXiv
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Autori principali: Gräßle, Benedikt, Bohne, Nis-Erik, Sauter, Stefan A.
Natura: Preprint
Pubblicazione: 2022
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author Gräßle, Benedikt
Bohne, Nis-Erik
Sauter, Stefan A.
author_facet Gräßle, Benedikt
Bohne, Nis-Erik
Sauter, Stefan A.
contents The Scott-Vogelius finite element pair for the numerical discretization of the stationary Stokes equation in 2D is a popular element which is based on a continuous velocity approximation of polynomial order $k$ and a discontinuous pressure approximation of order $k-1$. It employs a "singular distance" (measured by some geometric mesh quantity $ Θ\left( \mathbf{z}\right) \geq 0$ for triangle vertices $\mathbf{z}$) and imposes a local side condition on the pressure space associated to vertices $\mathbf{z}$ with $Θ\left( \mathbf{z}\right) =0$. The method is inf-sup stable for any fixed regular triangulation and $k\geq 4$. However, the inf-sup constant deteriorates if the triangulation contains nearly singular vertices $0<Θ\left( \mathbf{z}\right) \ll 1$. In this paper, we introduce a very simple parameter-dependent modification of the Scott-Vogelius element such that the inf-sup constant is independent of nearly-singular vertices. We will show by analysis and also by numerical experiments that the effect on the divergence-free condition for the discrete velocity is negligibly small.
format Preprint
id arxiv_https___arxiv_org_abs_2212_09673
institution arXiv
publishDate 2022
record_format arxiv
spellingShingle The pressure-wired Stokes element: a mesh-robust version of the Scott-Vogelius element
Gräßle, Benedikt
Bohne, Nis-Erik
Sauter, Stefan A.
Numerical Analysis
65N12, 65N30, 76D07
The Scott-Vogelius finite element pair for the numerical discretization of the stationary Stokes equation in 2D is a popular element which is based on a continuous velocity approximation of polynomial order $k$ and a discontinuous pressure approximation of order $k-1$. It employs a "singular distance" (measured by some geometric mesh quantity $ Θ\left( \mathbf{z}\right) \geq 0$ for triangle vertices $\mathbf{z}$) and imposes a local side condition on the pressure space associated to vertices $\mathbf{z}$ with $Θ\left( \mathbf{z}\right) =0$. The method is inf-sup stable for any fixed regular triangulation and $k\geq 4$. However, the inf-sup constant deteriorates if the triangulation contains nearly singular vertices $0<Θ\left( \mathbf{z}\right) \ll 1$. In this paper, we introduce a very simple parameter-dependent modification of the Scott-Vogelius element such that the inf-sup constant is independent of nearly-singular vertices. We will show by analysis and also by numerical experiments that the effect on the divergence-free condition for the discrete velocity is negligibly small.
title The pressure-wired Stokes element: a mesh-robust version of the Scott-Vogelius element
topic Numerical Analysis
65N12, 65N30, 76D07
url https://arxiv.org/abs/2212.09673