Physics and Astronomy Thesis Proposal Presentation

Thomas Dombrowski

“From single to many: swimming and collective behavior at intermediate Reynolds numbers”

Living organisms dynamically self-assemble into large clusters exhibiting complex collective behavior, such as bait balls and bird flocks. This emergent behavior of “active matter” has been demonstrated at many length scales using both biological and artificial active components. At the microscale, viscosity dominates over inertia (think of trying to swim in molasses) where bacteria and self-propelled nanoparticles swarm; at the macroscale, inertia dominates over viscosity, and examples include schools of fish, swarms of robots and crowds of people. Most active matter models have either completely ignored hydrodynamic interactions or have focused on very small or very large scales, where mathematical approximations can be made. However, there is a whole region in-between, i.e. at the mesoscale, where both viscous and inertial forces are important, and active matter remains completely unexplored. Mesoscale active matter opens up numerous possibilities for materials science and describes millions of different organisms that we can study for their biology and as model systems. In this study, computational fluid dynamics is used to model and characterize mesoscale swimmers, examine their pairwise interactions, and ultimately build a framework to understand their collective behavior.

This presentation will be held remotely via Zoom. Please see department listservs for more details.