Dresden 2006 – wissenschaftliches Programm

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SYSS: Structure Formation and Self-Organization in non-equilibrium Systems

SYSS 3: Structure Formation and Self-Organization in non-equilibrium Systems - Poster

SYSS 3.21: Poster

Donnerstag, 30. März 2006, 16:00–18:00, P1

Spatially localized stationary convection in binary mixtures with weakly negative Soret effect — •Dominik Jung and Manfred Luecke — Institut für Theoretische Physik, Universität des Saarlandes, Postfach 151150, D-66041 Saarbrücken, Germany

The convective behaviour of a binary fluid layer (e. g. ethanol-water) heated from below has been simulated numerically for realistic boundary conditions. Because of the negative Soret effect ethanol migrates to the colder regions in a temperature gradient. The corresponding influence on buoyancy distribution makes a wide range of convection structures possible.

We found spatially localized patches of stationary overturning convection rolls (LSOC) which are stably surrounded by quiescent fluid. LSOCs can coexist at the same heating with spatially periodic stationary overturning convection (SOC), extended waves of travelling rolls (TW) and localized traveling waves (LTW). Furthermore they coexist in two basic symmetry types as well as with different roll numbers.

We identify the localization mechanism of LSOCs to be an advective redistribution of the ethanol concentration. The connection of LSOCs to standing and moving convection fronts is investigated.