EXPERIMENTAL STUDY OF FRICTION FACTOR FOR GROUNDWATER FLOW IN A SINGLE ROUGH FRACTURE  

作　　者：CHEN Zhou QIAN Jia-zhong LUO Shao-he ZHAN Hong-bin 

机构地区：[1]School of Resources and Environmental Engineering, Hefei University of Technology, Hefei 230009, China [2]Department of Resources and Environment, Henan Polytechnic University, Jiaozuo 454010, China [3]Department of Geology and Geophysics, Texas A and M University, College Station, TX 77843-3115, USA

出　　处：《Journal of Hydrodynamics》2009年第6期820-825,共6页水动力学研究与进展B辑（英文版）

基　　金：supported by the Program for New Century Excellent Talents in Universities (Grant No.NCET-06-0541);the National Natural Science Foundation of China (Grant Nos.40672154,40772153)

摘　　要：To study the relationships between the friction factor f and the flow type in a single rough fracture, the formulae of f for both unconfined and confined flows are deduced based on previous studies. The relationships between f and the Reynolds number （Re） for different relative roughnesses are investigated experimentally. The Moody-type diagram, based on the deduced formula of f, is also plotted and the hydraulic characteristics of the flow in a rough fracture are analyzed. Results show that the Moody-type diagram of the experiment has a similar distribution to that of the conventional Moody diagram. It is found that the value of f in the experiment is much smaller than that of the conventional Moody diagram and turbulent flow appears easier for rough fractures, which can be explained by the separation phenomenon in boundary layers. The critical Re ranging from 650 to 700 in rough fractures is concluded based on the experimental results. It also can be concluded that the friction factor f is related not only with the Re and the relative roughness but also with the absolute roughness.To study the relationships between the friction factor f and the flow type in a single rough fracture, the formulae of f for both unconfined and confined flows are deduced based on previous studies. The relationships between f and the Reynolds number （Re） for different relative roughnesses are investigated experimentally. The Moody-type diagram, based on the deduced formula of f, is also plotted and the hydraulic characteristics of the flow in a rough fracture are analyzed. Results show that the Moody-type diagram of the experiment has a similar distribution to that of the conventional Moody diagram. It is found that the value of f in the experiment is much smaller than that of the conventional Moody diagram and turbulent flow appears easier for rough fractures, which can be explained by the separation phenomenon in boundary layers. The critical Re ranging from 650 to 700 in rough fractures is concluded based on the experimental results. It also can be concluded that the friction factor f is related not only with the Re and the relative roughness but also with the absolute roughness.

关 键 词：friction factor rough fracture Moody diagram critical Reynolds number （ Re ） boundary layer 

分 类 号：TH117.1[机械工程—机械设计及理论] TV855[水利工程—水利水电工程]