> C. Ruyer-Quil
Formation and flow regimes of a thin liquid film under partial wetting condition in cylindrical geometry
P. Hayoun, A. Letailleur, J. Teisseire, E. Verneuil, F. Lequeux and E. Barthel
Polymers such as PVC and Silicone are low cost material widely used in the industry to produce tubing for fluid transport. Most of these applications involve repeated, intermittent flow of liquids which can lead to unwanted contamination. This study aims at better understanding contamination mechanisms during intermittent flow in polymer tubing, and at elucidating the relation between flow parameters, chemical affinity and contamination rates. We investigate, experimentally and theoretically, flow regimes as well as dewetting process at the triple line, induced by gravity flow of a vertical liquid slug in a cylindrical geometry. Our results for Newtonian fluids evidence a succession of thin film formation, ridge creation in the thickness profile, oscillatory regime and destabilization leading to substrate contamination. Our theoretical approach is a tentative for explaining behaviours observed experimentally such has meniscus deformation and thin film deposition, dewetting and drainage of the film, wave motion in the thin liquid film.