文献类型：期刊文献

英文题名：Critical hydraulic gradient for nonlinear flow through rock fracture networks: The roles of aperture, surface roughness, and number of intersections

作者：Liu, Richeng[1];Li, Bo[1,2];Jiang, Yujing[1,3,4]

机构：[1]Nagasaki Univ, Sch Engn, Nagasaki 8528521, Japan;[2]Shaoxing Univ, Rock Mech & Geohazards Ctr, Shaoxing 312000, Peoples R China;[3]Shandong Univ Sci & Technol, State Key Lab Min Disaster Prevent & Control Cofo, Qingdao 266590, Peoples R China;[4]Shandong Univ Sci & Technol, Minist Sci & Technol, Qingdao 266590, Peoples R China

年份：2016

卷号：88

起止页码：53

外文期刊名：ADVANCES IN WATER RESOURCES

收录：SCI-EXPANDED(收录号：WOS:000371311800007)、、EI(收录号：20160801992789)、Scopus(收录号：2-s2.0-84957599230)、WOS

基金：This study has been partially funded by grant-in-aid for Young Scientists (B), Japan (grant no. 15K18302), China Scholarship Council (CSC) and National Natural Science Foundation of China (grant no. 51379117). These supports are gratefully acknowledged. The data presented in this article are available from the corresponding author.

语种：英文

外文关键词：Critical hydraulic gradient; Discrete fracture network; Surface roughness; Intersection; Aperture; Nonlinear flow

外文摘要：Transition of fluid flow from the linear to the nonlinear regime has been confirmed in single rock fractures when the Reynolds number (Re)exceeds some critical values, yet the criterion for such a transition indiscrete fracture networks (DFNs) has received little attention. This study conducted flow tests on crossed fracture models with a single intersection and performed numerical simulations on fluid flow through DFNs of various geometric characteristics. The roles of aperture, surface roughness, and number of intersections of fractures on the variation of the critical hydraulic gradient J(c) for the onset of nonlinear flow through DFNs were systematically investigated. The results showed that the relationship between hydraulic gradient Wand flow rate can be well quantified by Forchheimer's law, when J drops below J(c) it reduces to the widely used cubic law, by diminishing the nonlinear term. Larger apertures, rougher fracture surfaces, and a greater number of intersections in a DFN would result in the onset of nonlinear flow at a lower J(c). Mathematical expressions of J(c) and the coefficients involved in Forchheimer's law were developed based on multi-variable regressions of simulation results, which can help to choose proper governing equations when solving problems associated with fluid flow in fracture networks. (C) 2015 Elsevier Ltd. All rights reserved.