title: Fractal model and Lattice Boltzmann Method for Characterization of Non-Darcy Flow in Rough Fractures.
abstract: The irregular morphology of single rock fracture significantly influences subsurface fluid flow and gives rise to a complex and unsteady flow state that typically cannot be appropriately described using simple laws. Yet the fluid flow in rough fractures of underground rock is poorly understood. Here we present a numerical method and experimental measurements to probe the effect of fracture roughness on the properties of fluid flow in fractured rock. We develop a series of fracture models with various degrees of roughness characterized by fractal dimensions that are based on the Weierstrass-Mandelbrot fractal function. The Lattice Boltzmann Method (LBM), a discrete numerical algorithm, is employed for characterizing the complex unsteady non-Darcy flow through the single rough fractures and validated by experimental observations under the same conditions. Comparison indicates that the LBM effectively characterizes the unsteady non-Darcy flow in single rough fractures. Our LBM model predicts experimental measurements of unsteady fluid flow through single rough fractures with great satisfactory, but significant deviation is obtained from the conventional cubic law, showing the superiority of LBM models of single rough fractures.
authors.affiliation: State Key Laboratory of Coal Resources &Safe Mining, China University of Mining &Technology, Beijing 100083, China.|State Key Laboratory for Geomechanics &Deep Underground Engineering, China University of Mining &Technology, Xuzhou 221116, China.|School of Mechanics and Civil Engineering, China University of Mining and Technology, Beijing 100083, China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Ju
authors.affiliation: State Key Laboratory for Geomechanics &Deep Underground Engineering, China University of Mining &Technology, Xuzhou 221116, China.
authors.forename: Qingang
authors.initials: Q
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Coal Resources &Safe Mining, China University of Mining &Technology, Beijing 100083, China.|Department of Engineering Mechanics, School of Aerospace, Tsinghua University, Beijing 100084, China.
authors.forename: Jiangtao
authors.initials: J
authors.lastname: Zheng
authors.affiliation: State Key Laboratory of Coal Resources &Safe Mining, China University of Mining &Technology, Beijing 100083, China.
authors.forename: Chun
authors.initials: C
authors.lastname: Chang
authors.affiliation: Key Laboratory of Energy Engineering Safety and Mechanics on Disasters, The Ministry of Education, Sichuan University, Chengdu 610065, China.
authors.forename: Heping
authors.initials: H
authors.lastname: Xie