Waltzing Worms: the dynamics of plant-animal collective vortex structures

Add to your list(s) Download to your calendar using vCal

• George Fortune, University of Cambridge, UK
• Friday 14 May 2021, 16:00-17:00
• GKB 100 Fluid Mechanics Webinar Series.

If you have a question about this talk, please contact virginia mullins.

Circular milling, a stunning manifestation of collective motion, is found across the natural world, from fish shoals to army ants. It has been observed recently that the plant-animal worm Symsagittifera roscoffensis exhibits circular milling behaviour, both in shallow pools at the beach and in Petri dishes in the laboratory. Here in this talk, we investigate this phenomenon, through experiment and theory, from a fluid dynamical viewpoint, focusing on the effect that an established circular mill has on the surrounding fluid. Unlike systems such as confined bacterial suspensions and collections of molecular motors and filaments that exhibit spontaneous circulatory behaviour, and which are modelled as force dipoles, the front-back symmetry of individual worms precludes a stresslet contribution. Instead, singularities such as source dipoles and Stokes quadrupoles are expected to dominate. A series of theoretical models is presented to understand the contributions of these singularities to the azimuthal flow fields generated by a mill, in light of the particular boundary conditions that hold for flow in a Petri dish. A model that treats a circular mill as a rigid rotating disc that generates a Stokes flow is shown to capture basic experimental results well, and gives insights into the emergence and stability of multiple mill systems.

This talk is part of the DAMTP info aggregator series.

This talk is included in these lists:

• All CMS events
• CMS Events
• DAMTP info aggregator
• Fluid Mechanics
• GKB 100 Fluid Mechanics Webinar Series
• Interested Talks
• bld31

Note that ex-directory lists are not shown.