Transcript Understanding the Dynamics of Soap Bubble Pinch-off Courtney Cromartie, Daniel Lathrop, Sonali Shukla.

Understanding the Dynamics
of Soap Bubble Pinch-off
Courtney Cromartie, Daniel Lathrop, Sonali Shukla
Inspiration for Project
Soap Film Topology Talk with Keith Moffatt
Unfolding a mobius strip
Singularities in catenoids
What About a Blown Bubble?
Stages of Pinch-off
Apparatus Design
Experimental Set-up
High-speed video camera
2,000 fps, 140 x 160 pixel frame
Pressurized Air
Designed a valve system to control the delivery
of air to the nozzle
External Triggering Device
Provided precision control timing of camera
and air burst
Optimizing Bubble Dynamics
Soap Solution
60 ml distilled water, 10 ml Dawn
dishwashing liquid, 3 ml glycerol
Careful balance of pressure and air burst length
to produce:
Symmetric
Single-pinch off events
Consistently
Edge Tracing & Image Analysis
z - z0 = (internal wall location) – (location of internal collapse)
Controlling Forces
Proposed that surface tension and kinetic
energy of fluid control the process of pinchoff
Dimensional Analysis of force equality
uncovers a 2/3’s power law between length
and time.
Preliminary Results from 10 Events
Early Stages
of Collapse
Later Stages of
Collapse
Closing Thoughts
Kinetic Energy and Surface Tension likely
play a role in the early stages of pinch-off
A camera with a higher frame rate and
better resolution would yield more
definitive results close to pinch-off
Special Thanks To:
Daniel Lathrop & Sonali Shukla
UMD TREND Program
National Science Foundation