摘要
目前工程中应用的各种流速分布都应当看作是紊流运动的基本方程(Navie-Stokes方程)在不同条件下的近似解,因此有不少的学者试图从标度指数出发寻求流速分布的规律。以长江、黄河实测资料为例,从分形标度的角度出发去探讨天然河道垂线流速分布的规律。研究结果表明:天然河道垂线流速确实存在着分形现象,分维数可以反映垂线流速分布的均匀程度,分维数越大,垂线流速分布越均匀;一般情况下,长江垂线流速的分维数要大于黄河的分维数,并且同一条河道的不同位置分维数不同。
The different velocity distributions used in present engineering should be taken for approximation solution of the basic equations of turbulent movement(Navier-Stokes equations)under different conditions,so many scholars tried to find the law of velocity distribution from the scaling index.Based on the measured data of the Yangtze River and the Yellow River,we explore the vertical velocity distribution patterns of the nat- ural river from the aspect of fractal scale.The exploration results show that:vertical velocity of natural rivers do exist fractal phenomenon,and the di- mensions can reflect the uniformity of velocity distribution,the greater dimension,the more uniform vertical velocity of the flow.The vertical velocity dimension of Yangtze River is greater than that of Yellow River,and it has different dimensions at different locations of the same river.
出处
《人民长江》
北大核心
2008年第18期17-19,共3页
Yangtze River
关键词
分形理论
分维数
流速分布
天然河道
fractal theory
fractal dimension
velocity distribution
natural river
