Regensburg 2002 – scientific programme

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DY: Dynamik und Statistische Physik

DY 46: Poster

DY 46.70: Poster

Thursday, March 14, 2002, 15:30–18:00, D

Imbibition Dynamics of Randomly Structured Two-Dimensional Media — •Dimitrios Geromichalos, Frieder Mugele, and Stephan Herminghaus — Abt. Angewandte Physik, Uni Ulm, Albert-Einstein-Allee 11, 89069 Ulm

We dipped two roughened glass plates with a changeable average separation of some µm into a liquid reservoir and recorded the fronts. The mean height of the fronts was found to be ∝ √t. For the smallest separation the boundary line became very rough and the formation of overhangs and bubbles was observed. We determined the roughness exponent χ from the height differences of the spatial correlation function. At small length scales we found χ ≈ 0.8, above a crossover-length there is χ ≈ 0.6, as predicted by the Kardar Parisi Zhang equation. The value of the crossover length matches the value predicted by the phase field model [M. Dubé et al., Phys. Rev. Lett. 83, 1628 (1999)]. An alternative explanation therefore is given by another non-local model [V. Ganesan and H. Brenner, Phys. Rev. Lett. 81, 578 (1998)]. Finally our results may explain the broadly scattered values aquired by previous experiments conducted with Hele-Shaw cells which yielded much bigger χ than predicted by local theories.