Dynamics of fluid interfaces

Interfaces such as between water and air or water and oil hold a special kind of energy called surface energy or surface tension. At small length scale, typically below 1 cm the surface energy, possibly with gravitational energy, kinetic energy or viscous dissipation dictates the shape and evolution of interfaces.The purpose of this course is to provide a basic understanding of interfacial phenomena going from the shape of rain drops, the fragmentation of a jets, the water repellent properties of leaves to the bursting of soap bubbles.

The concepts and physical quantities are always introduced from an experimental observation. In the derivations, we favor scaling laws instead of detailed mathematical calculations in order to extract the essence of the underlying physics.

The laws of capillarity were established at the beginning of the nineteenth century. However research in this field is very active because of its position at the frontier between applied and fundamental science. For instance, the development of microfluidic devices has raised a number of questions related to the dynamics of fluid interfaces. The design of smart interfaces with original wetting properties has enabled the manipulation of drops on solids. The development of new tools both at micro-scale (atomic force microscopy) and macro-scale (digital high speed imaging) has revolutionized experiments.

In every part, we have included illustrative videos from recent publications, either kindly provided by colleagues throughout the world or from our own research. For those who want to go beyond this course, references to research contributions in scientific journals are given.