Berlin 2018 – wissenschaftliches Programm

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BP: Fachverband Biologische Physik

BP 8: Active Matter DY II (joint session DY/CPP/BP)

BP 8.3: Vortrag

Montag, 12. März 2018, 16:00–16:15, BH-N 243

Self propulsion of droplets driven by an active permeating gel — •Reiner Kree and Annette Zippelius — Inst. f. Theoret. Physik, Univ. Göttingen, Friedrich-Hund. Pl. 1, 37077 Göttingen

We discuss the flow field and velocity of active droplets, which are driven by body forces residing on a rigid gel. The latter is modeled as a porous medium which gives rise to permeation forces. In the simplest model, the Brinkmann equation, the porous medium is characterized by a single length scale l, the square root of the permeability. We compute the flow fields, the translational and rotational velocity of the droplet and the energy dissipation as a function of l. We show that the model gives rise to non-monotic behaviour of the droplet velocities and the dissipated power as functions of the gel fraction. As l changes from large to small values, the properties of the medium change from a simple viscous fluid to a Darcy medium. We discuss the behaviour of flow, velocities and force densities as these limits are approched.