Thin liquid film stability via multi-component lattice Boltzmann simulations*

We numerically study the thin liquid film stability via multi-component lattice Boltzmann simulations. The thin liquid film instability triggers a dewetting process, i.e., the reverse process to the spontaneous spreading of a liquid droplet on a solid surface, which takes place when the liquid film is forced to stay in contact with a hydrophobic wall. This situation leads the system to live in a metastable state, whose stability properties depend on the initial height of the film as well as on the surface wetting properties. In this work, we first controlled if our in-house Shan-Chen multi-component lattice Boltzmann model is valid to investigate the break-up of a thin liquid film placed on a flat wall: an infinitesimal perturbation of the initial interface of the liquid film is observed to be sufficient to trigger the film-to-droplet rupture. In this case, we investigated the conditions that trigger this transition in terms of the film surface tension, initial film height, and wetting properties of the flat surface. A further difficulty is then introduced, by analysing how strongly the presence of a solid surface with complex geometry impacts the stability scenario.