48 citations · 121 across the 12 of their papers we have counts for
13 papers
Heat Conduction with Phase Change in Permafrost Modules of Vegetation Models
David Hötten, Jenny Niebsch, Ronny Ramlau +1
We consider the problem of heat conduction with phase change, that is essential for permafrost modeling in Land Surface Models and Dynamic Global Vegetation Models. These models re…
Matrix-free Monolithic Multigrid Methods for Stokes and Generalized Stokes Problems
Daniel Jodlbauer, Ulrich Langer, Thomas Wick +1
We consider the widely used continuous - quadrilateral or hexahedral Taylor-Hood elements for the finite element discretization of the Stokes an…
A short note on inf-sup conditions for the Taylor-Hood family -
Walter Zulehner
We discuss two types of discrete inf-sup conditions for the Taylor-Hood family - for all with in 2D and 3D. While in 2D all results hold fo…
The Elasticity Complex: Compact Embeddings and Regular Decompositions
Dirk Pauly, Walter Zulehner
We investigate the Hilbert complex of elasticity involving spaces of symmetric tensor fields. For the involved tensor fields and operators we show closed ranges, Friedrichs/Poincar…
Robust Preconditioners for Multiple Saddle Point Problems and Applications to Optimal Control Problems
Alexander Beigl, Jarle Sogn, Walter Zulehner
In this paper we consider multiple saddle point problems with block tridiagonal Hessian in a Hilbert space setting. Well-posedness and the related issue of preconditioning are disc…
Preconditioning Inverse Problems for Hyperbolic Equations with Applications to Photoacoustic Tomography
Alexander Beigl, Otmar Scherzer, Jarle Sogn +1
This paper is concerned with robust preconditioning of wave equations constrained linear inverse problems from boundary observation data. The main result of this paper is a concept…
A new mixed isogeometric approach to Kirchhoff-Love shells
Katharina Rafetseder, Walter Zulehner
For Kichhoff-Love shell problems a new mixed formulation solely based on standard spaces is presented. This allows for flexibility in the construction of discretization space…
Schur complement preconditioners for multiple saddle point problems of block tridiagonal form with application to optimization problems
Jarle Sogn, Walter Zulehner
The importance of Schur complement based preconditioners are well-established for classical saddle point problems in . In this paper we extend the…
A decomposition result for Kirchhoff plate bending problems and a new discretization approach
Katharina Rafetseder, Walter Zulehner
A new approach is introduced for deriving a mixed variational formulation for Kirchhoff plate bending problems with mixed boundary conditions involving clamped, simply supported, a…
On the analysis of block smoothers for saddle point problems
Lorenz John, Ulrich Rüde, Barbara Wohlmuth +1
In this article, we discuss several classes of Uzawa smoothers for the application in multigrid methods in the context of saddle point problems. Beside commonly used variants, such…
On Closed and Exact Grad-grad- and div-Div-Complexes, Corresponding Compact Embeddings for Tensor Rotations, and a Related Decomposition Result for Biharmonic Problems in 3D
Dirk Pauly, Walter Zulehner
It is shown that the first biharmonic boundary value problem on a topologically trivial domain in 3D is equivalent to three (consecutively to solve) second-order problems. This dec…
A Robust Multigrid Method for Isogeometric Analysis using Boundary Correction
Clemens Hofreither, Stefan Takacs, Walter Zulehner
We consider geometric multigrid methods for the solution of linear systems arising from isogeometric discretizations of elliptic partial differential equations. For classical finit…
Stability Estimates and Structural Spectral Properties of Saddle Point Problems
Wolfgang Krendl, Valeria Simoncini, Walter Zulehner
For a general class of saddle point problems sharp estimates for Babuška's inf-sup stability constants are derived in terms of the constants in Brezzi's theory. In the finite-dimen…