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Center for Nonlinear Studies |
The dynamics of millimeter sized air bubbles rising through still water are investigated using precise ultrasound velocity measurements combined with high speed video. From measurements we deduce the forces acting on the bubble and we tie the dynamics of the bubble’s wake to observed oscillatory instabilities of the bubble’s path: planar zigzag and spiraling motion. Based on our measurement, and using Kirchoff’s equations, we build a system of four ordinary differential equations which effectively model these dynamics. In this model, the zigzag and the spiral motions result from the same underlying subcritical bifurcation of the lift force during the wake instability.
Host: Bob Ecke, T-CNLS