Tuesday, May 14, 2013

Physics of Bubbles: supercomputer needed.

It took one of the world's most powerful supercomputers five days to model a simple childhood past time: popping bubbles.

Image credit: Andreas Bastian

Researchers at the Lawrence Berkeley National Laboratory and at the University of California Berkeley have mathematically described the evolution of a cluster of bubbles. The research was published May 10, 2013 in the journal Science.

Bubbles and foams have been notoriously difficult to model mathematically. Whether a bubble pops and how its neighbors rearrange depend on phyiscal factors that take place at multiple length and time scales. For most materials, the thin fluid membrane between bubbles are thinner than a human hair, contain a proportionally huge amount of gas, and depend on the chemistry of the fluid.

In their paper, the researchers report that they were able to separate out the physical dynamics that take place at different length and time scales in a series of equations.

They had equations to describe how over many seconds, gravity thins out the fluid bubble wall as the bubble approaches popping. A separate set of equations described how, in less than a second, the bubbles rearrange after a neighbor pops. Still more predicted how liquid would flow at the intersection between bubbles.

By writing out a series of equations that describe different aspects of bubble dynamics, the researchers were able to overcome a longstanding challenge of describing a system that covers many time and length scales.

Combining these equations, the researchers used the Department of Energy's National Energy Research Scientific Computing Center (NERSC) to create a computer-generated model of popping bubbles.

In industry, clusters of bubbles belong to a class of materials called foams. From ocean froth, to soapy detergents, fire retardants, and bicycle helmets, foams play an large role in our day to day lives.  The researchers hope that their robust model of foam physics will enable accurate modeling and innovation for a variety of industrial foams.


  1. Can we please retire the human hair, RCH or otherwise, as a unit of measurement?

    1. Do you have a better suggestion?

    2. Yeah, micrometers or fractions of a milimeter.

      0.1mm or 100um respectively.