CHARACTERISTIC-EDDY DECOMPOSITION OF TURBULENCE IN A CHANNEL
CHARACTERISTIC-EDDY DECOMPOSITION OF TURBULENCE IN A CHANNEL
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DOI：
10.1017/s0022112089000741
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发表时间：
1989-03-01
影响因子：
3.7
通讯作者：
MOSER, RD
中科院分区：
文献类型：
--
作者：
MOIN, P;MOSER, RD
将适当的正交分解技术（Lumley 分解）应用于通道中的湍流，通过将速度场分解为具有随机系数的特征涡流来提取相干结构。在均匀空间方向上，使用散粒噪声展开的概括来确定特征涡流。在这种展开中，特征涡流的傅立叶系数无法从二阶统计中获得。使用三种不同的技术来确定这些系数的相位：（i）基于双谱的技术，（ii）空间紧凑性要求，以及（iii）功能连续性论证。发现这三种技术的结果非常相似。这些技术和散粒噪声扩展的含义在附录中讨论。研究发现，主导涡流对湍流动能的贡献高达 76%。在二维和三维中，特征涡流由横跨流向涡流的喷射区域组成，流向涡流以大约 100 个壁单位的非常短的流向距离离开壁。
The proper orthogonal decomposition technique (Lumley's decomposition) is applied to the turbulent flow in a channel, to extract coherent structures by decomposing the velocity field into characteristic eddies with random coefficients. In the homogeneous spatial directions a generalization of the shot-noise expansion is used to determine the characteristic eddies. In this expansion the Fourier coefficients of the characteristic eddy cannot be obtained from second-order statistics. Three different techniques are used to determine the phases of these coefficients: (i) a technique based on the bispectrum, (ii) a spatial compactness requirement, and (iii) a functional continuity argument. Results from these three techniques are found to be very similar. The implications of these techniques and the shot-noise expansion are discussed in the Appendix. The dominant eddy is found to contribute as much as 76% to the turbulent kinetic energy. In two and three dimensions, the characteristic eddies consist of an ejection region straddled by streamwise vortices which leave the wall in a very short streamwise distance of approximately 100 wall units.