Soft Matter and Complex Systems Seminar
sala 1.40, ul. Pasteura 5
2019-03-15 (09:30) 
Marek Bukowicki (IPPT PAN)
Effect of bending on sedimentation of two deformable microparticles
Particles settling under gravity in a viscous fluid (Re<<1) interacthydrodynamically, what can lead to complex dynamics. In this talk Ipresent system of two elongated particles in symmetric, or almostsymmetric, configurations.
It is shown that symmetric pair of rigid, straight rods during thesettlement perform periodic motions. In case of elastic fibres,hydrodynamic interactions lead to spontaneous reorientation of particles,such that they adopt horizontal and parallel orientation. I explain originof this behaviour, showing that it is caused by the curved shape adoptedby the filaments. As a consequence, similar dynamics is found for rigidparticles: curved rods and trumbbells.We also investigate the long-term dynamics of particles, once the parallelconfiguration has been reached. It turns out that fibres effectivelyattract or repel each other, depending on their elasticity or shape. Inthe intermediate range, the interparticle distance is fixed.
Additionally, consequences of a slight asymmetry of the initialconfiguration are investigated, among which interesting patterns of thedynamics have been found.
The system presented in this talk is an interesting example ofself-organization, attraction or repulsion of particles caused entirely bythe hydrodynamic interactions between particles settling in an externalfield.
It is shown that symmetric pair of rigid, straight rods during thesettlement perform periodic motions. In case of elastic fibres,hydrodynamic interactions lead to spontaneous reorientation of particles,such that they adopt horizontal and parallel orientation. I explain originof this behaviour, showing that it is caused by the curved shape adoptedby the filaments. As a consequence, similar dynamics is found for rigidparticles: curved rods and trumbbells.We also investigate the long-term dynamics of particles, once the parallelconfiguration has been reached. It turns out that fibres effectivelyattract or repel each other, depending on their elasticity or shape. Inthe intermediate range, the interparticle distance is fixed.
Additionally, consequences of a slight asymmetry of the initialconfiguration are investigated, among which interesting patterns of thedynamics have been found.
The system presented in this talk is an interesting example ofself-organization, attraction or repulsion of particles caused entirely bythe hydrodynamic interactions between particles settling in an externalfield.