Microfluidics, Jovian Climate Change Highlight DFD Meeting

Recent advances in micro-fluidics and the use of vortex dynamics to predict an impending global climate change for the planet Jupiter were among the highlights of the annual meeting of the APS Division of Fluid Dynamics (DFD), held November 24-26 at Southern Methodist University and the University of Texas at Austin. More than 950 contributed papers were presented, in addition to two honor lectures and eight invited lectures. Also featured was the annual Gallery of Fluid Motion, in which researchers submit aesthetically pleasing, insightful displays of still pictures, computer graphics, and video clips of computational and experimental fluid dynamics.

A fundamental understanding of thermocapillary flow on homogeneous and chemically patterned surfaces has led to the development of miniaturized automated systems for transporting small liquid volumes through networked arrays, which are rapidly expanding diagnostic capabilities in medicine, genomic research and materials science. Princeton University's Sandra Troian described her work on such microfluidic devices, which combine micromechanical and electrokinetic techniques for metering flow in closed channels. Her team has demonstrated that programmable thermal maps can be used in conjunction with chemical substrate patterning to modulate thermocapillary flow. This method provides electronic control over the direction, flow rate, mixing, splitting and trapping of discrete droplets or continuous streams.

Kenny Breuer of Brown University discussed the mechanics of fluids at the micron and submicron scale, which are critical to the widespread growth of microengineering and the development of a new generation of micron- and nanometer- scale diagnostic techniques. He identified several remaining challenges, ranging from the prediction of viscous damping and lubrication effects in MEMs, to the design of microengines and the understanding of bacterial propulsion.

The planet Jupiter has a 100-year climate cycle, according to Philip Marcus of the University of California, Berkeley, who predicts that within the next seven years, the day- averaged temperature of the Jovian atmosphere at the height of the visible clouds will change by 10' circa or more. That change will be preceded by a decrease in the number of large Jovian vortices, and followed by violent instabilities along the planet's eastward-going jet streams, which in turn will lead to a repopulation of the Jovian vortices in the atmosphere.

This year's recipients of the APS Fluid Dynamics Prize and Otto Laporte Award were featured in special invited honor session. Andrea Prosperetti of Johns Hopkins University (the Laporte Award recipient) spoke about bubbles, which he described as "a tiny cloud shielding a mathematical singularity". Despite their brief lifetime, bubbles give rise to a wealth of fascinating physical phenomena: underwater noise, sonoluminescence, and boiling, among others.

The 2002 DFD meeting also featured a special U.S./Mexican mini-symposium on the dynamics and interactions of vortices. Invited speakers from both the U.S. and leading institutions in Mexico addressed a diverse range of topics, including electrically driven vortices in multipolar magnetic fields, the stability of elliptically inhomogeneous rodons, vortex pair dynamics and instabilities, Hamiltonian contour dynamics, and coupled oscillations in a vortex chain.