Anomalous roughening of viscous fluid fronts in spontaneous imbibition.
We report experiments on spontaneous imbibition of a viscous fluid by a model porous medium in the absence of gravity. The average position of the interface satisfies Washburn's law. Scaling of the interface fluctuations suggests a dynamic exponent z approximately 3, indicative of global dynamics driven by capillary forces. The complete set of exponents clearly shows that interfaces are not self-affine, exhibiting distinct local and global scaling, both for time (beta = 0.64 +/- 0.02, beta(*) = 0.33 +/- 0.03) and space (alpha = 1.94 +/- 0.20, alpha(loc) = 0.94 +/- 0.10). These values are compatible with an intrinsic anomalous scaling scenario.
Soriano
J
J
Experimentalphysik I, Universität Bayreuth, Germany.
Mercier
A
A
Planet
R
R
Hernández-Machado
A
A
Rodríguez
M A
MA
Ortín
J
J