Singularite anguleuse d'une ligne de contact en movement sur un substrat solide (Corner singularity of a contact line moving on a solid substrate)

In conditions of partial wetting and at sufficiently high capillary number Ca, a dynamic contact line that recedes on a solid surface assumes a 'saw-tooth' shape. We show that the flow inside this liquid 'corner' is a similarity solution of the lubrication equations governing steady thin-film flows in which the free surface is cone shaped. The interface slope Φ#169; defined in its symmetry plane is linked to the corner angle 2φ by the approximate relationship Φ#169;3≈(3/2) Catan2φ. We also suggest a possible explanation of droplet emission from the corner which occurs when φ reaches π/6.