Dresden 2014 – wissenschaftliches Programm

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DF: Fachverband Dielektrische Festkörper

DF 22: Slow Dynamics in Glasses and Granular Matter I (Joint Focus Session with DY and CPP)

DF 22.7: Vortrag

Donnerstag, 3. April 2014, 11:45–12:00, HÜL 186

rheology near jamming-the influence of lubrication forces — •moumita maiti and Claus Heussinger — Georg-August University of Goettingen, Goettingen, Germany

The talk discusses the role of different dissipation forces on the rheological properties of highly dense non-Brownian suspensions. The focus is on the random close packing limit ("jamming") where particle motion is limited due to steric volume exclusion. We define a simplified lubrication force where we change the dissipation mechanisms by tuning the range of the interaction. Two densities are considered, one is near jamming the other further away. For both densities, a crossover is seen from 'inertia' dominated flow to viscous flow by changing the lubrication range. Interestingly, we observe that velocity fluctuations are independent of the different dissipation mechanisms ("universal")near jamming. Away from jamming this universality is lost and an unexpected non-monotonic dependence is seen. We present an understanding of our findings in terms of geometric constraints of random-close packing and a decoupling of dissipative forces and particle trajectories.