Upcoming Events
- Tuesday, 24.09.2024, 10:15 (WIAS-406)
- Seminar Nichtlineare Optimierung und Inverse Probleme
Bernhard Höveler, Technische Universität Berlin, Institut für Mathematik:
An analogue for the Gramian of a linear quadratic regulator for nonlinear control systems and its approximability by finite rank operators
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, 4. Etage, Weierstraß-Hörsaal (Raum: 406)
Host
WIAS Berlin
- Tuesday, 01.10.2024, 10:00 (WIAS-405-406)
- Seminar Numerische Mathematik
Prof. Dr. Philip Lederer, Universität Hamburg:
High-order projection-based upwind method for implicit large eddy simulation
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, 4. Etage, Raum: 405/406
Abstract
We assess the ability of high-order (hybrid) discontinuous Galerkin methods to simulate under-resolved turbulent flows. The capabilities of the mass conserving mixed stress-yielding method as structure resolving large eddy simulation (LES) solver are examined. A comparison of a variational multiscale model to no-model or an implicit model approach is presented via numerical results. In addition, we present a novel approach for turbulent modeling in wall-bounded flows which can be interpreted as an extension of the classical variational multiscale idea to implicit LES via discontinuous Galerkin methods. This new technique called high-order projection-based upwind (HOPU) technique provides a more accurate representa- tion of the actual subgrid scales in the near wall region and gives promising results for highly under-resolved flow problems. We consider the turbulent channel flow and periodic hill flow problem as well as a flow over an Eppler airfoil.
Host
WIAS Berlin
- Wednesday, 09.10.2024, 11:30 (WIAS-405-406)
- Seminar Interacting Random Systems
Christopher Renaud Chan, Université Grenoble Alpes:
tba
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, 4. Etage, Raum: 405/406
Further Informations
Seminar Interacting Random Systems (Hybrid Event)
Host
WIAS Berlin
- Wednesday, 30.10.2024, 10:00 (WIAS-405-406)
- Berliner Oberseminar „Nichtlineare partielle Differentialgleichungen” (Langenbach-Seminar)
Prof. Dr. Tomáš Roubíček, Czech Academy of Sciences, Tschechische Republik:
Time discretization in visco-elastodynamics at large displacements and strains in the Eulerian frame
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, 4. Etage, Raum: 405/406
Abstract
The fully-implicit time discretization (i.e. the backward Euler formula) is applied to compressible nonlinear dynamical models of viscoelastic media in the Eulerian description, i.e. in the actual deforming configuration. The Kelvin--Voigt rheology or also, in the deviatoric part, the Jeffreys (also called anti-Zener) rheology describing a (possibly nonlinear) creep or a rate-dependent plasticity are considered. Both a linearized convective model at large displacements with a convex stored energy and the fully nonlinear large strain variant with a (possibly generalized) polyconvex stored energy are considered. The time-discrete suitably regularized schemes (suggesting an implementable numerical strategy) are devised for both these heavily nonlinear cases. The numerical stability and, considering the multipolar 2nd-grade viscosity, also convergence towards weak solutions are proved, exploiting the convexity of the kinetic energy when written in terms of linear momentum instead of velocity. In the fully nonlinear case, the examples of neo-Hookean and Mooney--Rivlin materials are presented. A comparison with models of viscoelastic barotropic fluids is also made and thermodynamical extension is outlined, too.
Further Informations
Oberseminar “Nichtlineare Partielle Differentialgleichungen” (Langenbach Seminar)
Host
Humboldt-Universität zu Berlin
WIAS Berlin