摘要
The mechanism of the flow resistance in open channels and pipelines is of vital importance for various critical issues related to the water flow.The Nikurade’s method of calculating the friction factor is not applicable in some cases.It is necessary to consider the influence of the vortex volume surrounding the vegetation and to study the hydrodynamic characteristics of the vegetated channels.This paper analyzes the variation of the vortices created by the surface roughness of different types and different sizes and proposes new definitions of the hydraulic radius and the equivalent roughness height.With consideration of the skin friction and the form drag,on the basis of the force balance equation,a novel calculation method is used for the friction factor,and this method is verified by experimental data.The hydrodynamic mechanism of the flow resistance revealed in this study may serve as a theoretical basis for hydraulic engineers to calculate the friction factor.
基金
Projects supported by the National Natural Science Foundation of China(Grant No.51979275)
This work was supported by the Jilin Province Key Research and Development Plan Project(Grant No.20180201036SF)
the Open Research Fund of State Key Laboratory of Information Engineering in Surveying,Mapping and Remote Sensing,Wuhan University(Grant No.19R06)
the Open Research Project of the State Key Laboratory of Industrial Control Technology,Zhejiang University(Grant No.ICT20021)
the Chinese Universities Scientific Fund(Grant Nos.2020TC033,10710301).
