Shocks in inertial dewetting

We present the first observation of a shock in the fast dewetting of a wate r film (thickness e) from hydrophobic glass. The film dewets by the nucleat ion and growth of a dry patch (velocity V), surrounded by a rim which colle cts the liquid. The velocity of dewetting V(e) follows the Culik law for th e bursting of soap films, with a driving force including both capillarity a nd gravity. The profile of the rim is measured by the deflection of a laser beam. The shock is observed when the rim surfs on the immobile film at vel ocities V* > root ge, the velocity of gravity waves (g = gravitational acce leration) in shallow water. Ripples emitted in front of the rim give us a s ignature of the shock.