Berlin 2005 – wissenschaftliches Programm
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DY: Dynamik und Statistische Physik
DY 12: Fluid Dynamics II
DY 12.1: Vortrag
Freitag, 4. März 2005, 14:30–14:45, TU H3010
Stretch-flow of thin layers of Newtonian liquids: Fingering patterns and lifting forces — •Anke Lindner1, Didi Derks2, and Michael Shelley3 — 1PMMH, Ecole Supérieure de Physique et de Chimie Industrielles, 10, rue Vauquelin, 75231 Paris Cedex 05, France — 2Soft Condensed Matter, Debye Institute, Utrecht University, Princetonplein 5, 3584 CC Utrecht, The Netherlands — 3Applied Math Lab, Courant Institute, New York University, New York City, NY 10012, USA
We study the stretch flow of a thin layer of Newtonian liquid constrained between two circular plates. The evolution of the interface of the originally circular bubble is studied when lifting one of the plates at a constant velocity and the observed pattern is related to the measured lifting force. By comparing experimental results to numerical simulations using a Darcy’s law model we can account for the fully non-linear evolution of the observed fingering pattern. One observes an initial destabilization of the interface by growth of air fingers due to a Saffman Taylor like instability and then a coarsening of the pattern towards a circular interface until complete debonding of the two plates occurs. Numerical simulations reveal that when relating the observed patterns to the lifting force not only the number of fingers but also the amplitude of the fingering growth has to be taken into account. This is in agreement with the experimental observations.