Stability of a dry patch in a viscous flowing film
Laboratoire Matière et Systèmes Complexes, Université Paris Diderot, UMR 7057, 10 rue Alice Domon et Léonie Duquet, 75205 Paris Cedex 13, France
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We investigate the dewetting of liquid films flowing down an incline. At low flow rate we observe the formation of stationary dry patches edged with a liquid rim. Their shape can be predicted by a simple model in which the rim weight is balanced by surface tension. Above a critical flow rate per unit length Γc of typical scale Uclc (Uc capillary velocity, lc capillary length), these dry patches cannot remain stationary and are swept away. An improved model taking into account capillary effects linked to contact line curvature, hydrostatic pressure in the film and inertial effects predicts this loss of stability in good agreement with experiments for sufficiently high viscosity values.
© EDP Sciences, Springer-Verlag, 2009