Self-Organized Pattern Formation in Thin Liquid Films
Orateur : Michael Bestehorn
Brandenburg University of Technology, Cottbus – Senftenberg, Germany
Résumé :
In a liquid layer with a free surface several hydrodynamic instabilities may occur and may lead to self-organized pattern formation. The patterns can be seen as macroscopic motion of the fluid, surface deformations, temperature or concen- tration distributions etc. Their typical length scale is often linked to the layer’s depth. The first part of the lecture gives an overview on pattern forming systems with emphasis on thin liquid films. In this case and for a partially wetting substrate (small contact angle) a reduced theoretical description based on the lubrication approximation is possible. In the second part, the Faraday instability for thin films is discussed. Recent results on droplet formation and motion in parametrically driven systems will be presented [1,2]. Droplets on a horizontal substrate are moving laterally if the layer is vibrating with a certain frequency and amplitude.
[1] M. Bestehorn, Q. Han, A. Oron, Nonlinear pattern formation in thin liquid films under external vibrations, Phys. Rev. E 88, 023025 (2013)
[2] M. Bestehorn, laterally extended thin liquid films under external vibrations, Phys. Fluids 25, 114106 (2013)
Date et lieu : le Lundi 16 Mars 2015 à 11h00, salle de séminaires IRPHE