Biofilm streamers and fluid dynamics: from vortical flows at low Reynolds numbers to the unsteady dynamics of elastic filaments
Event details
| Date | 23.03.2012 |
| Hour | 13:00 › 14:00 |
| Speaker | Dr. Laura Guglielmini, Stanford University, Center for Turbulence Research, USA |
| Location | |
| Category | Conferences - Seminars |
Bacterial biofilms are ubiquitous in aquatic environments, generally develops in flow and adherent to surface and interfaces and have an enormous impact on medicine, process industry and ecology. Recent experiments observed the formation of thread-like biofilms, called streamers, in microchannels with corners and bends, floating in the middle plane of the channel and connected to the side walls at the inner corners. Motivated by this observation, we use numerical simulations and asymptotic analysis to show that at low-Reynolds number, in proximity of a corner or a change in the curvature of the side wall, the flow is three-dimensional and pairs of counter-rotating secondary vortical structures are present. This fact suggests an underlying hydrodynamic mechanism for the formation of streamers. Additionally, we model the streamer as a slender elastic filament and we discuss its time evolution and final shape in a viscous flow. Finally, the mentioned experimental observations lead us to study the response of an elastic fiber tethered to a plane wall and subjected to a stagnation point flow. We find that, for a critical value of the ratio between viscous and elastic forces, the filament is susceptible to a buckling instability at a supercritical bifurcation point. This last phenomenon is also relevant to a number of flow problems involving slender elastic fibers.
Practical information
- Informed public
- Free
- This event is internal
Organizer
- IGM, Prof. I Botsis
Contact
- Prof. I Botsis