H. Steiner1, B. Gschaider2
1Graz University of Technology/AT, 2ICE Strömungsforschung GmbH/AT
The dynamics of thin liquid films on solid substrates is basically governed by the complex interaction of various forces, such as inertial, graviational, viscous, capillary, or three-phase contact forces, acting for the most part on very different scales in time and space. Owing to this complex physics, there are still many open questions concerning the influence of varying fluid properties, the topology and wettability of the solid substrate, a potential local dewetting, the heat and mass transfer, chemical reations, etc., which have been attracting the scientific interest of many research groups. Thin film flows are also highly important in the industrial application, where they are typically met in coating of technical surfaces, or in wet processing technologies (surface cleaning, cleansing, etching). The strong discepancy of the relevant scales highly challenges an accurate numerical description of the flow, as the generally used Volume-of-Fluid(VoF)-based direct simulations become exceedingly expensive. Thin film approximations (TFA) have therefore been used as a computationally less costly alternative by many researchers. The depth-averaged computations associated with TFA were proven to reflect many essential features of the flow fairly well. The proposers of the minisymposium acquired much expertise on the topic in the particular field of liquid film flow on rotating disks, where the centrifugal forces may act as further source of film instability typically leading to a highly irregular waviness of the liquid surface. They carried out their computational investigations using VoF-based simulations as well as the TFA approach. An experimental test rig was available for validation based on optical observations.