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Study on Hysteresis Phenomenon and Local Non-equilibrium Turbulence in Couette-type Turbulent Flow

库埃特型湍流中滞后现象与局部非平衡湍流研究

基本信息

批准号：
03452123
负责人：
NAKABAYASHI Koichi
金额：
$ 3.26万
依托单位：
Nagoya Institute of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1991
资助国家：
日本
起止时间：
1991 至 1993
项目状态：
已结题

项目摘要

1. Firstly, turbulence structure in plane turbulent Couette flow has been studied. The results obtained are as follows. (1) Turbulence structure in the wall region is similar to that in the two-dimensional channel flow. In the core region, however, turbulence structure is very different from the latter case because of the uniform shear existing there. (2) As turbulence energy is produced only on the streamwise turbulence quantity, the anisotropy of turbulence is greater than that of the channel flow. (3) Distributions of velocity fluctuating components show Gaussian and tripple velocity correlation is almost zero. Viscous diffusion and dissipation of turbulence energy balance throughout the core region. Energy transport u, v and w is due to the pressure-strain. (4) Sinuisoidal change of mean velocity distribution has been measured in the spanwise derection, so that large-scale motions having spanwise scale of eddies are conjectured to exist.2. Secondly, Couette-Poiseuille type turbulen … More t flow has been studied to investigate the hysteresis phenomenon in the core region and the local non-equilibrium turbulence which have been measured on the turbulent Couette-type flow with an alternative pressure gradient, having both stationary wavy and moving flat walls. The distribution of velocity in the Couette-Poiseuille type flow has been considered indepedently under the parameters of Reynolds number Re^<**>=hu_<**>/nu and d tau /dy. The results obtained are as follows. (1) Low of the wall is given by U^+=f(y^+, mu^<-1>), where y^+=u_<**>/nu and mu^<-1>=(nu d tau/dy)/(rhou_<**>^3). We clarified the effects of Re^<**> on Van Driest damping factor A^+ and additive constant B of the log-law for preferable (mu^<-1><0) and adverse (mu^<-1>>0) pressure gradient cases, respectively. (2) For positive value of d tau/dy, effects of betaXIrhou_<**>^2h/(d tau/dy) and Re^<**> on the half-power law is clarified. (3) Profiles of velocity defect law in the turbulent core region are only related to whether the flow is Couette-type (beta>-0.5) or poiseuille-type (beta<-0.5). Less

1.首先研究了平面湍流Couette流中的湍流结构。得到的结果如下。 (1) 壁面区域的湍流结构与二维通道流中的湍流结构相似。然而，在核心区域，由于存在均匀剪切，湍流结构与后一种情况有很大不同。 (2) 由于湍流能量仅在流向湍流量上产生，因此湍流的各向异性大于通道流的各向异性。 (3) 速度脉动分量的分布表明高斯和三重速度相关性几乎为零。整个核心区域的湍流能量平衡的粘性扩散和耗散。能量传输 u、v 和 w 是由压力应变引起的。 (4)在翼展方向测量到平均速度分布的正弦变化，推测存在翼展尺度涡流的大尺度运动。2．其次，研究了Couette-Poiseuille型湍流，以研究核心区域的滞后现象和局部非平衡湍流，这是在具有替代压力梯度的湍流Couette型流上测量的，具有静止的波状壁和移动的平坦壁。在雷诺数Re^<**>=hu_<**>/nu和d tau /dy参数下独立考虑了Couette-Poiseuille型流中的速度分布。得到的结果如下。 (1) 墙的低由 U^+=f(y^+, mu^<-1>) 给出，其中 y^+=u_<**>/nu 和 mu^<-1>=(nu d tau/dy)/(rhou_<**>^3)。我们分别阐明了 Re^<**> 对优选 (mu^<-1><0) 和不利 (mu^<-1>>0) 压力梯度情况下的 Van Driest 阻尼因子 A^+ 和对数定律的加性常数 B 的影响。 (2)对于d tau/dy 为正值，明确了betaXIrhou_<**>^2h/(d tau/dy)和Re^<**>对半幂律的影响。 (3) 湍流核心区速度缺陷定律的分布仅与流动是库埃特型(β>-0.5)还是泊肃叶型(β<-0.5)有关。较少的