A constitutive-relationship model for film flow on rough fracture surfaces

摘要

Film flow on fracture surfaces may be an important mechanism for fast flow in unsaturated fractured rocks. Incorporating this mechanism into a numerical model requires knowledge of constitutive relationships for film flow. Based on fractal concepts and a conceptual argument of Tokunaga et al. that water films could be treated as analogues to water in unsaturated porous media, a simple constitutive-relationship model has been developed. The validity of the model is supported by excellent agreements between calculation results and experimental observations for two different fracture surfaces.