Anomalous interface roughening in porous media: Experiment and model

Abstract

We report measurements of the interface formed when a wet front propagates in paper by imbibition and we find anomalous roughening with exponent \ensuremath{\alpha}=0.63\ifmmode\pm\else\textpm\fi{}0.04. We also formulate an imbibition model that agrees with the experimental morphology. The main ingredient of the model is the propagation and pinning of a self-affine interface in the presence of quenched disorder, with erosion of overhangs. By relating our model to directed percolation, we find \ensuremath{\alpha}\ensuremath{\simeq}0.63.