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Applied Mathematics Colloquium


Friday, April 27, 11:30 am
Cullimore Lecture Hall II
New Jersey Institute of Technology

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Stability of Rising Bubbles

Andrea Prosperetti


Department of Mechanical Engineering, Johns Hopkins University, Baltimore, MD

& Department of Applied Physics, University of Twente, The Netherlands






Abstract


The talk will summarize some recent work on (1) Leonardo's paradox, i.e. the instability of the rectilinear path of ascent of bubbles in a liquid, and (2) the loss of axial symmetry of a long (Taylor) bubble rising in a vertical tube. For the first problem, a linear stability analysis carried out computationally reveals several aspects of the loss of stability of the axisymmetric flow past an ellipsoidal bubble translating along the axis of symmetry. In particular, the central role of vorticity is elucidated. For the second problem, use is made of a simplified model which reveals the physical origin of the loss of axial symmetry in counter-current flow. While also involving bubbles, there will be a bonus feature with little relation to the previous two problems ...