Research on Liquid Bridges Relates to Infant Health and Planetary Environments

The Case Western Reserve University team of Charles Rosenblatt, Philip L. Taylor, and J. Iwan D. Alexander have used time-varying magnetic levitation techniques to study the dynamic behavior of fluids. In a recent Physical Review Letter article the team examined the collapse of a cylindrical liquid bridge when the total body force (gravitational + magnetic) was suddenly changed from zero. They found that the time to collapse is independent of bridge length, and discovered a new scaling relationship to describe the phenomenon. They also applied a 1-D slice model to the problem, finding good agreement between experimental results and theory. More recently they examined the resonance behavior of liquid bridges by subjecting the bridge to a temporally-periodic magnetic field (over and above the d.c. magnetic field required to simulate microgravity conditions). The team was able to determine the resonance frequency as a function of the Bond number and slenderness ratio on the bridges.

This technique, which is applicable to studies of dynamic surface tension, will be used to examine the transport of pulmonary surfactants and the resulting dynamic change in surface tension. The goal is to determine how best to treat premature infants who are unable to synthesize enough surfactant to facilitate proper functioning of their lungs.

With the ability to simulate gravitational environments not only in space but also on other planets, and the ability to vary the total body force with time, the work of Rosenblatt, Taylor, and Alexander has been reported in both the scientific and popular press. Discover Magazine and Pour la Science (the French Scientific American) recently carried stories about their work.