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DY: Fachverband Dynamik und Statistische Physik

DY 33: Poster II

DY 33.36: Poster

Donnerstag, 14. März 2013, 17:00–19:00, Poster C

Convection onset in a transient diffusive boundary layer at high Rayleigh numbers — •Stephan Messlinger, Christoph Kramer, Wolfgang Schöpf, and Ingo Rehberg — Experimentalphysik V, Universität Bayreuth, 95440 Bayreuth

We observe the onset of Soret driven convection in a colloidal suspension of thermosensitive microgel particles in water. The suspension exhibits a strong positive Soret-effect, resulting in large solutal Rayleigh numbers even for low temperature gradients. When heated from below in a classical convection cell, the convective instability does not set in uniformly over the system height, but starts in the steep concentration profiles established at the cell boundaries. We report on the latency time of the convection onset and the transient behaviour of the fluid motion shortly thereafter.