Dewetting hydrodynamics in 1+1 dimensions - art. no. 026304

A model for the phase transition between partial wetting and dewetting of a substrate has been formulated that explicitly incorporates the hydrodynami c flow during the dewetting process in 1 + 1 dimensions. The model simulate s a fluid layer of finite thickness on a substrate in coexistence with a dr y part of the substrate and a gas phase above the substrate. Under nonequil ibrium ''dewetting'' conditions, the front between the dry part and the wet part of the surface moves towards the wet part inducing hydrodynamic flow inside the wet layer. In more general terms, the model handles two immiscib le fluids with a freely movable interface in an inhomogeneous external forc e field. Handling the interface by a new variant of the phase-field model, we obtain an efficient code with well-defined interfacial properties. In pa rticular, the (free) energy can be chosen at will. We demonstrate that our model works well in the viscosity range of creeping flow and we give qualit ative results for the higher Reynolds numbers. Connections to experimental realizations are discussed.