幂律流体延伸表面逆来流边界层特性分析与数值模拟

Analysis and numerical simulation of boundary layer separation flow on the stretching surface of power law fluids

首先利用量级分析理论对幂律流体延伸表面边界层流动进行分析,得到边界层厚度的量级和影响因素;引入量纲为1变量,将动量边界层的控制方程转化为量纲为1的控制方程组.数值求解了具有不同幂律指数n的流体在平板逆来流且平板运动参数ζ不同的情况下的层流边界层流场,分析了幂律指数n和平板运动参数ζ对动量边界层厚度、量纲为1速度分布和量纲为1剪切力分布的影响规律.结果表明,速度边界层的分布不仅和平板运动参数有关,而且和幂律指数有关.

A theoretical analysis of boundary layer flow on the continuous moving surface of power law fluids was carried out based on the theory of dimensional analysis of the fluid dynamics. The magnitude and the influencing factor of the laminar boundary layer thickness were obtained. The governing equations of mass and momentum were transformed into the dimensionless form by introduc- ing dimensionless variables. The flow fields of different power-law index fluids with different velocity ratio parameters were presented numerically. The characteristics of the flow and the influence of power-law index and velocity ratio parameter on the flow were analyzed. The results show that the dimensionless velocity and shear stress depend not only on the velocity ratio parameter of the plate, but also on the power law index.