Berlin 2015 – scientific programme
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 54: Wetting, Micro and Nanofluidics (joint session CPP, DY)
CPP 54.3: Talk
Wednesday, March 18, 2015, 15:30–15:45, C 243
Dynamic Trapping of Sliding Drops on Wetting Defects — •Andrea Cavalli1, Michiel Musterd2, Rudy Lagraauw1, Dieter 't Mannetje1, Dirk van den Ende1, and Frieder Mugele1 — 1University of Twente, MESA+ Institute for Nanotechnology; Physics of Complex Fluids, Enschede, The Netherlands — 2Delft University of Technology, Delft, The Netherlands
We present a numerical analysis of the dynamic interaction of sliding drops on an inclined plate with wetting defects. Our three-dimensional model, developed with OpenFOAM allows us to describe intertial and viscous effects, as well as the internal degrees of freedom of the droplet. We observe that the ability of a drop to deform and stretch enhances the strenght and range fo the wetting defect, as compared to a simplified analytic description of a non-deformable drop. Yet, the key physical parameters, namely the ration between trapping strength and driving force as well as the ratio between interial and viscous time scale prevail as governing control parameters. We further investigate the role of the strength, size and steepness of the wetting defect in retaining the drop. Finally, we compare our simulations with trapping experiments on electrowetting obstactles. The quantitative agreement shows that the trapping of sliding drops follows a universal behavior, which is largely independent of the specific nature of the defect.