Organized structures in a compressible, turbulent boundary layer
Organized structures in a compressible, turbulent boundary layer
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DOI：
10.1017/s0022112087002258
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发表时间：
1987-09
影响因子：
3.7
通讯作者：
E. F. Spina;A. Smits
中科院分区：
文献类型：
--
作者：
E. F. Spina;A. Smits
实验结果表明，在可压缩湍流边界层中存在有组织结构。在3马赫零压力梯度边界层中采用热丝和壁面压力传感器阵列得到了结果。采用条件采样的VITA方法推导了壁面平均压力事件和整个边界层的质量通量事件；这些结果在定性上与不可压缩流动的结果相似。通过对三线探针的中间热丝进行条件反射，发现存在与边界层厚度相当的高度结构的证据。此外，采用两点条件采样表明，可以通过质量通量事件来提取平均压力事件。从这个过程中，我们发现这些结构在向下游移动时保持了它们的形状，而且它们的跨度范围非常有限。从两根热丝之间以及热丝与壁面压力传感器之间的相关关系推断出的角度表明，边界层的大部分平均结构倾斜约为45°。这一结果与在超音速边界层纹影照片中观察到的结构吻合得很好。瞬时角的测量表明结构角分布广泛，大尺度结构的一般行为与壁面湍流的发夹环模型一致。
Experimental results are presented that show the existence of organized structures in a compressible, turbulent boundary layer. Results were obtained using arrays of hot wires and wall pressure transducers in a Mach-3 zero-pressure-gradient boundary layer. The VITA method of conditional sampling was used to deduce average pressure events at the wall and mass flux events throughout the boundary layer; these results show qualitative similarity to those found in incompressible flows. By conditioning upon the middle hot wire from a three-wire probe, evidence is found suggesting that structures exist of a height comparable with the boundary-layer thickness. Furthermore, two-point conditional sampling was used to show that an average pressure event could be extracted by conditioning upon mass-flux events. From this procedure we found that the structures maintain their shape as they travel downstream and also that their spanwise extent is very limited. The inferred angle from correlations between two hot wires, and between a hot wire and a wall-pressure transducer, indicate that the average structure is inclined at approximately 45° for a large part of the boundary layer. This result agrees well with structures observed in schlieren photographs of supersonic boundary layers. Measurements of the instantaneous angle show a wide distribution of structure angles, and the general behaviour of the large-scale structures is consistent with the hairpin loop model of wall turbulence.