Homogeneous, Isotropic Flow in Grid Generated Turbulence
Homogeneous, Isotropic Flow in Grid Generated Turbulence
复制标题
网格生成湍流中的均匀各向同性流
DOI：
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发表时间：
2000
期刊：
影响因子：
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通讯作者：
D. Munoz
中科院分区：
文献类型：
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作者：
Riccardo Tresso;D. Munoz
使用三维热线风速计和遍历机构完成了详细的网格生成的湍流分析，以识别方形网格下游的均匀、各向同性的流动区域。沿着风洞测试部分的中心线以及方形网格下游的整个风洞横截面的空间记录三维脉动速度测量。不同网格尺寸和雷诺数的湍流强度在三个主速度方向的每个方向上的范围从最小 0.2% 到最大 2.2%。使用协方差方法确定了几种湍流条件和下游位置的空间均匀性和各向同性。理论上，协方差应该渐近接近于零；然而，在实践中，这是不可能实现的。需要主观判断来确定三个协方差的方差达到接近于零的值的下游位置。平均标准偏差提供了一个估计值，用于定义确定均匀、各向同性流动的开始所需的极限或主观阈值
Detailed grid generated turbulent analysis has been completed using a three-dimensional hot-wire anemometer and traversing mechanism to identify a homogeneous, isotropic flow region downstream of a square mesh. The three-dimensional fluctuating velocity measurements were recorded along the centerline of a wind tunnel test section and spatially over the entire wind tunnel cross section downstream of the square mesh. Turbulent intensities for various grid sizes and Reynolds numbers ranged from a minimum of 0.2 percent to a maximum of 2.2 percent in each of the three principal velocity directions. Spatial homogeneity and isotropy were determined for several turbulent flow conditions and downstream positions using the method of covariances. Covariances, in theory, should approach zero asymptotically; however, in practice, this was not achievable. A subjective judgment is required to determine downstream location where the variance of the three covariances reaches a value close to zero. The average standard deviation provides an estimate for defining the limit or subjective threshold needed to determine the onset of homogeneous, isotropic flow