Swimmers and deformable bodies in active matter ("Microswimmers lecture series")

Date

Jan 9, 2019

Time

4:30 PM - 5:30 PM

Speaker

Thomas R. Powers

Affiliation

Brown University

Series

TUD Vorlesungsserie - Microswimmers

Language

en

Main Topic

Physik

Other Topics

Biologie, Physik, Mathematik, Chemie

Host

Juliane Simmchen, Veronika Magdanz, Benjamin Friedrich

Description

We present a theoretical study of a swimming undulating sheet and a passive deformable interface in the isotropic phase of an active nematic liquid crystal. In both problems, activity changes the effective shear viscosity, reducing it to zero at a critical value of activity. For the swimmer, we expand in the sheet amplitude to find that the correction to the swimming speed due to activity is inversely proportional to the effective shear viscosity. Our perturbative calculation becomes invalid near the critical value of activity; using numerical methods to probe this regime, we find that activity enhances the swimming speed by an order of magnitude compared to the passive case. In the case of the passive interface, we study several geometries, including a planar film, spherical droplets, and cylinders. We show how activity affects the mode structure and the stability of an interfaces in these different geometries; activity can cause a flat film or spherical drop to go unstable, and alter the growth rate of the Raleigh-Plateau instability of a cylinder.

Links

• Microswimmer lecture series homepage

Last modified: Jan 7, 2019, 10:31:45 AM