On convection velocities in turbulent shear flows
On convection velocities in turbulent shear flows
复制标题
DOI：
10.1017/s002211206400132x
复制
发表时间：
1964-11
影响因子：
3.7
通讯作者：
-J.;-A.;-B.
中科院分区：
文献类型：
--
作者：
-J.;-A.;-B.
本文讨论了剪切流中湍流脉动的有效对流速度的定义问题，并讨论了不同学者所采用的定义。在圆形射流剪切层中的一个实验表明，通常的定义，根据波动的时空相关性的峰值，产生对流速度，其大小取决于所选择的空间或时间间隔的值。另一种方法表明，通过将湍流场视为谐波行波的叠加，可以定义波数/速度谱，该波数/速度谱适合于定义波数依赖的对流速度和总对流速度，这两者都具有真实的物理意义。描述了一种获得光谱的实验技术，并给出了射流剪切层中一个位置的结果。
The problem of defining an effective velocity of convection for turbulent fluctuations in a shear flow is considered, and the definitions adopted by various workers are discussed. An experiment in the shear layer of a circular jet has shown that the usual definitions, based on peaks of the space-time correlations of the fluctuations, yield convection velocities whose magnitudes depend on the value of space or time separation chosen. An alternative approach shows that, by considering the turbulent field as a superposition of harmonic travelling waves, a wave-number/velocity spectrum can be defined that lends itself to the definition of a wave-number-dependent convection velocity and an overall convection velocity, both of which have real physical significance. An experimental technique is described for obtaining the spectrum, and results are presented for one position in the shear layer of the jet.