Berlin 2012 – wissenschaftliches Programm
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DY: Fachverband Dynamik und Statistische Physik
DY 5: Soft Matter I
DY 5.1: Vortrag
Montag, 26. März 2012, 15:00–15:15, MA 004
Onset of flow in a confined model colloidal glass — •Pinaki Chaudhuri1,2 and Juergen Horbach1 — 1Institut für Theoretische Physik II, Heinrich Heine-Universität Düsseldorf, Universitätsstr. 1, 40225 Düsseldorf, Germany — 2Institut für Physik, Johannes Gutenberg-Universität Mainz, Staudinger Weg 7, 55099 Mainz, Germany
Understanding the mechanisms that build up flow in soft glassy systems remains an outstanding problem. In recent times, because of various practical applications, flow of such systems under confinement has also drawn considerable attention. Using numerical simulations, we study the onset of flow, under confinement, in a model colloidal glass under an externally applied stress. Typically, amorphous systems yield when the stress exceeds a threshold value (the yield stress) - we show that the time-scales for the onset of steady state flow rapidly increase as the applied stress is lowered towards the threshold. Moreover we observe that, in confinement, these time-scales depend on the nature of the imposed stress - e.g, they are longer for a Poiseuille flow, compared to a Couette flow. We further elucidate the microscopic process that are responsible for these increasing time-scales as well as the differences with the various applied stress fields.