title: Lattice model for spontaneous imbibition in porous media: the role of effective tension and universality class.
abstract: Recently, anomalous scaling properties of front broadening during spontaneous imbibition of water in Vycor glass, a nanoporous medium, were reported: the mean height and the width of the propagating front increase with time t both proportional to t(1/2). Here, we propose a simple lattice imbibition model and elucidate quantitatively how the correlation range of the hydrostatic pressure and the disorder strength of the pore radii affect the scaling properties of the imbibition front. We introduce an effective tension of liquid across neighboring pores, which depends on the aspect ratio of each pore, and show that it leads to a dynamical crossover: both the mean height and the roughness grow faster in the presence of tension in the intermediate-time regime but eventually saturate in the long-time regime. The universality class of the long-time behavior is discussed by examining the associated scaling exponents and their relation to directed percolation.
authors.affiliation: Department of Physics, Inha University, Incheon 402-751, Korea.
authors.forename: Deok-Sun
authors.initials: DS
authors.lastname: Lee
authors.affiliation: Theoretical Physics, Saarland University, 66041 Saarbrücken, Germany.
authors.forename: Zeinab
authors.initials: Z
authors.lastname: Sadjadi
authors.affiliation: Theoretical Physics, Saarland University, 66041 Saarbrücken, Germany.
authors.forename: Heiko
authors.initials: H
authors.lastname: Rieger
mesh_terms: D005898:Glass; D057446:Hydrodynamics; D008962:Models, Theoretical; D009038:Motion; D016062:Porosity; D011312:Pressure; D014867:Water
chemical_list: D014867:Water