The Gauss center research in multiscale scientific computation.
The general form of local bilinear functions
The scalar product of the FEM basis functions with non-intersecting supports vanishes. This property is generalized and the concept of local bilinear functional in a Hilbert space is introduced. The general form of such functionals in the spaces and is given.
The generalized finite volume SUSHI scheme for the discretization of the peaceman model
We demonstrate some a priori estimates of a scheme using stabilization and hybrid interfaces applying to partial differential equations describing miscible displacement in porous media. This system is made of two coupled equations: an anisotropic diffusion equation on the pressure and a convection-diffusion-dispersion equation on the concentration of invading fluid. The anisotropic diffusion operators in both equations require special care while discretizing by a finite volume method SUSHI. Later,...
The version of the boundary element method on polygonal domains with quasiuniform meshes
The version of the finite element method with quasiuniform meshes
The heat radiation problem: three-dimensional analysis for arbitrary enclosure geometries.
The Hierarchical Basis Multigrid Method.
The hierarchical basis multigrid method for convection-diffusion equations.
The h-p Version of the Finite Element Method for Elliptic Equations of Order 2m.
The hp-version of the boundary element method with quasi-uniform meshes in three dimensions
We prove an a priori error estimate for the hp-version of the boundary element method with hypersingular operators on piecewise plane open or closed surfaces. The underlying meshes are supposed to be quasi-uniform. The solutions of problems on polyhedral or piecewise plane open surfaces exhibit typical singularities which limit the convergence rate of the boundary element method. On closed surfaces, and for sufficiently smooth given data, the solution is H1-regular whereas, on open surfaces, edge...
The Indicatrix Method in Free Boundary Problems.
The invertibility of the isoparametric mappings for triangular quadratic Lagrange finite elements
A reference triangular quadratic Lagrange finite element consists of a right triangle with unit legs , , a local space of quadratic polynomials on and of parameters relating the values in the vertices and midpoints of sides of to every function from . Any isoparametric triangular quadratic Lagrange finite element is determined by an invertible isoparametric mapping . We explicitly describe such invertible isoparametric mappings for which the images , of the segments , are segments,...
The local solution of a parabolic-elliptic equation with a nonlinear Neumann boundary condition
We investigate a parabolic-elliptic problem, where the time derivative is multiplied by a coefficient which may vanish on time-dependent spatial subdomains. The linear equation is supplemented by a nonlinear Neumann boundary condition with a locally defined, -bounded function . We prove the existence of a local weak solution to the problem by means of the Rothe method. A uniform a priori estimate for the Rothe approximations in , which is required by the local assumptions on , is derived by...
The L.P.D.E.M., a mixed finite difference method for elliptic problems.
The method of fictitious right-hand sides
The paper deals with the application of a fast algorithm for the solution of finite-difference systems for boundary-value problems on a standard domain (e.g. on a rectangle) to the solution of a boundary-value problem on a domain of general shape contained in the standard domain. A simple iterative procedure is suggested for the determination of fictitious right-hand sides for the system on the standard domain so that its solution is the desired one. Under the assumptions that are usual for matrices...
The Method of Lines for Poisson's Equation with Nonlinear or Free Boundary Conditions.
The mixed problem for the Laplace equation on the rectangle
The mortar element method for three dimensional finite elements
The Mortar finite element method for Bingham fluids
This paper deals with the flow problem of a viscous plastic fluid in a cylindrical pipe. In order to approximate this problem governed by a variational inequality, we apply the nonconforming mortar finite element method. By using appropriate techniques, we are able to prove the convergence of the method and to obtain the same convergence rate as in the conforming case.
The mortar finite element method for Bingham fluids
This paper deals with the flow problem of a viscous plastic fluid in a cylindrical pipe. In order to approximate this problem governed by a variational inequality, we apply the nonconforming mortar finite element method. By using appropriate techniques, we are able to prove the convergence of the method and to obtain the same convergence rate as in the conforming case.