Reynolds number effects on wavelet components of self-preserving turbulent structures.
Reynolds number effects on wavelet components of self-preserving turbulent structures.
复制标题
DOI：
10.1103/physreve.79.046322
复制
发表时间：
2009-04
期刊：
影响因子：
--
通讯作者：
A. Rinoshika;Yu Zhou
中科院分区：
文献类型：
--
作者：
A. Rinoshika;Yu Zhou
研究了 Re_{theta}（基于尾流的自由流速度和动量厚度，theta）=1350 和 4600 时雷诺数对自守平面尾流中小波分解湍流结构的影响。使用两个正交阵列的 16 个 X 线、8 个圆柱体在 x/theta（x 是圆柱体下游的流向距离）=580 处进行了测量在 (x,y) 平面中，八个在 (x,z) 平面中。小波多分辨率技术用于分析测量的热线数据。该技术根据湍流结构的中心频率将湍流结构分解为多个分量，这些分量与湍流尺度相关。在两个雷诺数之间检查和比较相同中心频率下的截面流线和涡度轮廓，即湍流结构的可比尺度。在相对大到中等尺度的湍流结构中观察到明显的差异。这些差异进一步量化为不同尺度的湍流结构对雷诺应力、涡度方差和脉动速度的概率密度函数的贡献。大型结构对雷诺应力的贡献最大，并且对于较高的 Re_{theta}，这种贡献会下降。
The effect of the Reynolds number on the wavelet-decomposed turbulent structures in a self-preserving plane wake has been investigated for Re_{theta} (based on the free-stream velocity and momentum thickness, theta, of the wake) =1350 and 4600. Measurements were made at x/theta (x is the streamwise distance downstream of the cylinder) =580 for the circular cylinder using two orthogonal arrays of 16 X wires, eight in the (x,y) plane, and eight in the (x,z) plane. A wavelet multiresolution technique is used to analyze the measured hot-wire data. This technique decomposes turbulence structures into a number of components based on their central frequencies, which are linked with the turbulence scales. Sectional streamlines and vorticity contours at the same central frequency, i.e., the comparable scales of turbulent structures, are examined and compared between the two Reynolds numbers. Discernible differences are observed in the turbulent structures of relatively large to intermediate scales. The differences are further quantified in terms of contributions from the turbulent structures of different scales to the Reynolds stresses, vorticity variance, and probability density functions of the fluctuating velocities. The large-scale structure contributes most to the Reynolds stresses and this contribution drops for the higher Re_{theta}.