Berlin 2005 – scientific programme
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DY: Dynamik und Statistische Physik
DY 34: Poster
DY 34.51: Poster
Monday, March 7, 2005, 15:30–18:00, Poster TU D
Shear-driven flocculation of sticky spheres: crossover from kinetic aggregation to anisotropic percolation — •Kajetan Bentele1, Klaus Kroy1, and Hans Herrmann2 — 1Hahn-Meitner Institut Berlin — 2Universität Stuttgart
Recent advances in mode-coupling theory have lead to substantial progress in our understanding of the complex non-equilibrium phase behavior of dense, weakly adhesive hard spheres and the shear-melting of their kinetically arrested states. The situation at low densities, high shear rates and stronger attractions is still very controversial and various universal jamming "phase diagrams" have been proposed. We report numerical studies of a simple, highly idealized, 2-dimensional adhesive-hard-sphere fluid under shear. Although temperature effects and hydrodynamic interactions are (so far) neglected, we expect the simulation to be indicative of the anisotropic large-scale properties of strongly sheared flocculating colloids. In particular, these approximations allow us to derive a simple but efficient analytical expression for the gel time that accounts for the structural crossover from kinetic aggregation to (anisotropic) percolation. A modified Flory argument further elucidates the crossover mechanism.