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Bubble dynamics in a Hele-Shaw cell

Friday, November 12, 2021
3:00pm to 4:00pm
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Online Event
Anne Juel, Professor of Fluid Mechanics, University of Manchester,

What links a baby's first breath to adhesive debonding, enhanced oil recovery, filtration or multiphase microfluidics? These processes all involve two-phase flows in rigid or elastic confined vessels and are often prone to interfacial instabilities. The canonical viscous fingering instability, which occurs when air displaces a viscous fluid in the narrow gap between two parallel plates, offers a versatile testbed for such phenomena. In this talk, I will use both experiments and numerical simulations of depth-averaged models to explore several aspects of bubble dynamics in Hele-Shaw cells. I will first show how the onset of fingering can be suppressed when replacing the upper plate of the vessel with an elastic sheet. Interfacial flows in narrow gaps can also exhibit considerable disorder, but they are rarely investigated from a dynamical systems' perspective. I will show how compliance can promote rich multiplicity of front propagation modes in a channel before turning to bubble propagation in a rigid channel with a depth perturbation. There I will explore how the bubble's organised transient dynamics is orchestrated by weakly-unstable steady propagation modes, and how its long-term behaviour may be practically unpredictable.

For more information, please contact Michael Stramenga by email at [email protected] or visit https://caltech.zoom.us/j/84244180704?pwd=Mk5vVFdGZ2JPL1E2K0JiaXFuUEkrUT09.