Etienne Reyssat (PMMH-ESPCI) - Confined sliding droplets

A liquid drop placed on an inclined surface tends to move down under the action of its weight. This now classical model experiment exhibits a variety of droplet shapes and instabilities depending on the sliding velocity and relative role of viscosity and inertia in the motion. It has been used to investigate the properties of moving contact lines, and in particular to estimate viscous dissipation close to these singularities.
In a similar spirit, we propose to discuss contact line dissipation for droplets confined between closely spaced quasi-parallel walls. We will study the shapes and velocities of such sliding drops. In this model geometry, bulk and line effects may be measured more independently. We investigate contact line dissipation by studying the motion of drops on prewetted surfaces, a way to regularize the contact line singularity in a controlled manner. We will try to show how the results on this model system may shed light on more complex dynamic wetting experiments.