# Regensburg 2002 – wissenschaftliches Programm

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# DY: Dynamik und Statistische Physik

## DY 46: Poster

### DY 46.70: Poster

### Donnerstag, 14. März 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.