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DY: Dynamik und Statistische Physik

DY 21: Nichtlineare Stochastische Systeme

DY 21.4: Vortrag

Dienstag, 12. März 2002, 10:45–11:00, H3

A Universal Model for Inmiscible Fluid-Fluid Displacement in Homogeneous Disordered Porous Media. — •Rafael Rangel — ICA1, Univ. Stuttgart, Pfaffenwaldring 27, 70569 Stuttgart, Germany — Dpto. de Fisica, Univ. Simon Bolivar, Caracas, Venezuela

We study inmiscible fluid-fluid displacement in a homogenous disordered porous media in a regime where the displaced fluid has negliable viscosity. In our model we consider the interplay between viscosity forces and capillary forces, the ratio is denoted by r, the inverse of the caplillary number. We use a DLA type algorithm and consider a boundary condition at the interface of the two liquids, which takes into account the the viscous and the capillary pressure at the interface. This boundary condition makes the problem non linear. With computer simulations we generate patters of displacement and calculate the roughness exponent and the dynamic exponent. We find the roughness exponent depends on r, and ranges from around 0.5 for small r to a saturation value aorund 0.8 for large r. We also find strong fluctuation of these values during simulations due to cascade similar processes at the interface. Our results compare well with the experiments of Pon-zeng wong et. al. ( Phys. Tev. Lett.69, 3731(1992).