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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库埃特流的湍流结构。所得结果如下。(1)壁面区域的湍流结构与二维槽道流相似。而在核心区，由于存在均匀剪切，湍流结构与后一种情况有很大不同。(2)由于湍流能量只产生于流向湍流量，湍流的各向异性大于槽道流的各向异性。(3)速度脉动分量的分布呈高斯分布，三重速度相关性几乎为零。粘性扩散和湍流能量耗散在整个核心区的平衡。能量传输u、v和w是由于压力-应变。(4)在展向测量了平均速度分布的正弦变化，从而证实了具有展向尺度的涡的大尺度运动的存在.第二，Couette-Poiffuille型双曲型 ...更多信息本文研究了具有静止波纹壁和运动平壁的具有交替压力梯度的Couette型湍流流动，以研究核心区的滞后现象和局部非平衡湍流。在雷诺数Re^<**>=hu_<**>/nu和dtau/dy的参数下，分别考虑了Couette-Poietille型流动中的速度分布。所得结果如下。(1)壁的高度由U^+=f（y^+，mu^）给出<-1>，其中y^+=u_<**>/nu，mu^<-1>=（nu d tau/dy）/（rhou_<**>^3）。我们分别澄清了Re^<**>对较佳（mu^ <0）和不利（mu^ >0）压力梯度情况下的货车Driest阻尼因子A^+和对数律附加常数B的影响<-1><-1>。(2)当d τ/dy为正值时，阐明了β XIrhou_<**>^2h/（d τ/dy）和Re^<**>对半幂律的影响。(3)湍流核心区速度亏损律的分布只与流动是Couette型（β>-0.5）还是Poiquilille型（β <-0.5）有关。少