Dresden 2003 – wissenschaftliches Programm

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DY: Dynamik und Statistische Physik

DY 11: Fluid dynamics I

DY 11.5: Vortrag

Montag, 24. März 2003, 11:00–11:15, G\"OR/229

Large scale Marangoni convection in thin liquid films — •Andrey Pototsky, Michael Bestehorn und Uwe Thiele — Lehrstuhl fuer Theoretische Physik II, BTU Cottbus, Erich-Weinert- Str. 1, 03046 Cottbus, Germany

The Marangoni effect may lead to large scale instabilities in thin liquid films, heated from below. In very thin films (about 10-100 nm) there exists another destabilizing mechanism, called disjoining pressure and caused by interaction between the substrate and the free film surface. Both of these two mechanisms were studied simultaneously for the one-layer model in the lubrication approximation. In the absence of the disjoining pressure unstable film evolves until dry spots appear (rupture). In order to stabilize the evolution of the film we introduce short range van der Waals repulsive interaction. The initially flat film gets unstable if the temperature difference exceeds a certain critical value. On the initial stage of evolution, drops, holes, or labyrinths appear. The boundary between the hole- and drop-solutions is determined. Inhomogeneous steady state solutions in the case of cylindric symmetry are obtained. The typical evolution scenario is demonstrated by 3D-simulations of the thin film equation.