摘要
从运动学观点，根据紊流的随机脉动性质，未作任何假定，导出了脉动流速分解方程和相应的脉动应力分解方程，并从二阶对称张量的性质，简化了脉动应力分解方程，可用于封闭Ｒｅｙｎｏｌｄｓ方程，分析了管中紊流的脉动粘性系数在断面上的变化趋势，发现与流速分布同步，于是给出了合理的算式以代替Ｐｒａｎｄｔｌ，Ｌ的混合长假设，还可推广用于明槽中紊流和平板紊流边界层，均有满意的结果。
rom the viewpoint of kinetics and on the basis of the fluctuating characteristics of turbulence,a resolution equation of fluctuating velocity and its corresponding resolution equation of Reynolds-stress are derived without any assumption, From the characters of second order symmetrical tensor,the resolution equation of Reynolds stress is further simplified, and thus can be used to the closed Reynolds equation,The distribution of the eddy viscosity vT in the cross section of pipe flow is analysed,and is found to vary synchmously with the velocity,and thus a well formed hypothesis is obtained which can replace Prandtl's mixing length.
出处
《河海大学学报（自然科学版）》
CAS
CSCD
1994年第4期39-47,共9页
Journal of Hohai University(Natural Sciences)
基金
水利水电科学基金
关键词
紊流模式
随机脉动
粘性
流速
Fluctuating velocity Reynolds stress Eddy viscosity Turbulence model
