Veranstaltungen
Veranstaltungen der Fakultät für Mathematik
Integral Constitutive Equations for the Rheology of Glass-Forming Fluids, als mathkol ans
Termin
23.03.2016, 14.15 Uhr -
Veranstaltungsort
Mathematikgebäude, Seminarraum M614/616 (6. Etage)
Abstract
I discuss the combination of a microscopic theory for the rheological behavior
of glass-forming fluids and glasses with lattice Boltzmann (LB) simulations of
the macroscopic flow fields. Glass-forming fluids are characterized by slow
structural relaxation. Macroscopic flow interrupts this relaxation, and
pronounced nonlinear-rheology phenomena (such as shear thinning) arise.
Starting from a formally exact equation of motion for microscopic density
fluctuations, the mode-coupling theory of the glass transition derives a
constitutive relation for non-Newtonian stresses that takes the form of a set
of nonlinear integral equations. We solve (a simplified version of) these
integral constitutive equations with a hybrid-LB method. I discuss exemplary
results for the transient flows after startup and cessation of pressure-driven
flow. In particular, after cessation of the flow, long-lived residual stresses
arise that are predicted to persist indefinitely in the glass.
Vortragende(r)
Prof. Dr. Thomas Voigtmann
Herkunft der/des Vortragenden
DLR Köln / Heinrich-Heine-Universität Düsseldorf