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DY: Fachverband Dynamik und Statistische Physik
DY 46: Poster: Wetting, Nano- and Microfluidics
DY 46.7: Poster
Mittwoch, 9. März 2016, 18:15–21:00, Poster B2
Fluid invasion in porous media: front morphology, residual saturation, and the Cieplak-Robbins-transition — •Stephan Herminghaus1, Ralf Seemann2, Kamaljit Singh2, Hagen Scholl2, Marco Di Michiel3, and Mario Scheel3 — 1MPI für Dynamik und Selbstorganisation, Göttingen — 2Fakultät für Physik, Universität des Saarlandes, Saarbrücken — 3ESRF, Grenoble
The fluid front morphologies emerging during fluid invasion into random piles of spherical beads are investigated in real time by X-ray micro-tomography and analyzed theoretically. Depending on the wettability of the invaded medium, we observe two distinct displacement regimes exhibiting strongly different liquid front morphologies. These regimes are separated by a pronounced transition, at which the residual saturation of the defending liquid (RSD) changes abruptly by one order of magnitude. We show that the critical contact angle at which this transition takes place can be quantitatively predicted on the basis of a quasi-static consideration of the wetting geometry of the progressing front. Furthermore, we find that the RSD agrees, within experimental scattering, quantitatively with our predictions from analytical theory, without invoking any fitting parameter.