Viscous flow and diffusion through a stressed self-affine fracture
Abstract
Flow in fractures is frequently encountered in many different areas like in hydrology or for tight direct metal to metal contact joints used to perform sealing under severe thermodynamic conditions. The present work, is focused on the transport (viscous flow and diffusion) through a contact under normal stress between rough surfaces exhibiting self-affine properties. The objective is to examine the validity of synthetic fractal surfaces instead of real ones for self-affine structures. The validity is checked using two different real surfaces: a sand blasted surface and a lapped surface. The transmissivity and effective diffusivity tensors K and D are computed as the solution of the closure problems resulting from the upscaling of viscous flow and diffusion. The deformation of the contact is determined using an elastic- perfectly plastic model. The dependence of K and D and of the distribution of local contact areas upon the average contact pressure is compared for the real surfaces on the one hand and their analogues that were synthesized using a fractal approach on the other.