Critical point network for drainage between rough surfaces

Abstract

In this paper, we present a network method for computing two-phase flows between two rough surfaces with significant contact areas. Low-capillary number drainage is investigated here since one-phase flows have been previously investigated in other contributions. An invasion percolation algorithm is presented for modeling slow displacement of a wetting fluid by a non wetting one between two rough surfaces. Short-correlated Gaussian process is used to model random rough surfaces.The algorithm is based on a network description of the fracture aperture field. The network is constructed from the identification of critical points (saddles and maxima) of the aperture field. The invasion potential is determined from examining drainage process in a flat mini-channel. A direct comparison between numerical prediction and experimental visualizations on an identical geometry has been performed for one realization of an artificial fracture with a moderate fractional contact area of about 0.3. A good agreement is found between predictions and observations.

Fluid flow across a wavy channel brought in contact

“…Numerical analysis of the fluid flow through contact interfaces was carried out between real [4,47,48,17] or model rough topographies [36,14,34]. In contrast to the complexity and lack of scale separation of nominally flat realistic surface roughness, surface patterning allows to use the concept of scale separation to a certain extent and to limit the analysis to major geometrical features of the surface [40,41,35].…”