水利学报2017，Vol.48Issue(7)：779-790,12.DOI:10.13243/j.cnki.slxb.20160452
基于动理学理论的床沙冲刷函数
Bed sediment entrainment function based on kinetic theory
摘要
Abstract
A large part of previously obtained entrainment functions were derived empirically due to the difficulties in relating microscopic motion of particles to their statistical properties.Presented in this paper is a new entrainment function derived on the basis of Kinetic Theory for sediment transport.The entrainment function for bed sediment is defined in terms of Kinetic Theory as a statistical ensemble average of the upward boundary flux of bed sediment in per unit area and per unit time picked up from bed into motion by lift,drag due to turbulence,gravity and other stochastic forces.The velocity distribution function involved in the entrainment function is determined by means of the kinetic equation for sediment-laden flows,as permits us to consider the variety of forces that affect the motion of bed sediments.The entrainment function is also calibrated,verified and compared with 80 runs of 3 different experiments,and furthermore,it is applied to serve as the boundary condition in modeling suspended sediment distribution in a pure erosion experiment.The results show that,the entrainment function is not only theoretically well-grounded,it has a satisfactory accuracy in predicting bed sediment entrainment rates as well.It shows that 87.2％ of the calculated entrainment rates by the newly obtained entrainment function have a relative error falling into the range of [-0.5,0.5],indicating it has a comparatively higher accuracy in comparison with other functions.The entrainment function applied as the bed boundary condition also works well in reproducing the pure erosion processes.The entrainment function derived in this paper has the advantage over other methods in that it helps to provide a new approach to statistically associate the dynamic processes of microscopic motion of particles to macroscopic features of sediment transport.关键词
冲刷函数/动理学理论/速度分布函数/床沙冲刷通量Key words
entrainment function/Kinetic Theory/velocity distribution function/entrainment flux分类
建筑与水利引用本文复制引用
贾宝真,张磊,李肖男,钟德钰..基于动理学理论的床沙冲刷函数[J].水利学报,2017,48(7):779-790,12.基金项目
国家自然科学基金资助项目(51379102,51609264) （51379102,51609264）
