Dresden 2003 – scientific programme

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DY: Dynamik und Statistische Physik

DY 11: Fluid dynamics I

DY 11.4: Talk

Monday, March 24, 2003, 10:45–11:00, G\"OR/229

Study of Marangoni instabilities in two-fluid systems using the phase-field formalism — •Rodica Borcia and Michael Bestehorn — Lehrstuhl fuer Theoretische Physik II, Brandenburgische Technische Universitaet Cottbus, Erich-Weinert Strasse 1, 03046, Cottbus, Germany

We analyze a two-dimensional phase-field model designed to describe Marangoni convection in a liquid-gas system with deformable interface, heated from below. In the frame of this formalism one introduces an order parameter, called phase-field function, to characterize the phases. All the system parameters (viscosity, density, heat capacity and thermal conductivity) are assumed to vary continuously from liquid to gas bulk, through linear function of this phase-field function. Minimizing the free-energy functional of the system, extra terms appear in the Navier-Stokes equation, responsible for describing both Marangoni instabilities, with short and long wavelength. The evolution of the phase-field is described by Cahn-Hilliard equation, that assures the mass conservation. We report on two-dimensional simulations for both Marangoni instabilities. In the limit of sharp and rigid interfaces our results are compared with the literature.