Francois Blanchette, James Franck Institute, University of Chicago
Drops and Particles in a Fluid
ABSTRACT: This talk is intended as an overview of various ways in which particles and drops can interact with fluids. Both solid and fluid particles are considered, and the nature of their interactions with the fluid is very different in each case. Solid particles are typically heavier that the surrounding fluid and, when present in large numbers, may generate large scale fluid motions through their influence on density. Simulations of particle-laden gravity currents are presented as a natural example of this behavior and particular attention is given to the erosion patterns that such currents may generate. In contrast, the dynamics of liquid drops are subject to the presence of surface tension. Two examples of flows in which surface tension is dominant are presented. First, a fundamental fluid dynamics question is addressed: how does a drop coalesce with a horizontal interface, and why is multiple coalescence occasionally observed? Second, the dynamics of micro-fluidic devices, a man-made application in which drops travel in a tiny tube, are described in detail. Highly accurate computer simulations are used to study both problems.