A Numerical Study on Flow and Transport in a Rough Fracture with Self-affine Fractal Variable Apertures

Abstract

This paper presents the numerical study to examine the characteristics of fluid flow and solute transport in a rough fracture subject to effective normal stresses. The aperture distribution is generated by using the self-affine fractal model. In order to represent a nonlinear relationship between the supported normal stress and the fracture aperture, we combine a simple mechanical model with the local flow model. The solute transport is simulated using the random walk particle following algorithm. Results of numerical simulations show that the flow is significantly affected by the geometry of aperture distribution varying with the effective normal stress level, while it is slightly affected by the fractal dimension that determines the degree of the fracture surface roughness. However, solute transport is influenced by the effective normal stress as well as the fracture surface roughness.

Keywords:

• fractal dimension
• fracture network
• nonlinear hydromechanical effect
• self-affine fractal model
• single fracture