An experimental investigation of a large-scale structure of a two-dimensional backward-facing step by using advanced multi-point LDV
An experimental investigation of a large-scale structure of a two-dimensional backward-facing step by using advanced multi-point LDV
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DOI：
10.1007/s00348-003-0718-6
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发表时间：
2004-02
影响因子：
2.4
通讯作者：
N. Furuichi;T. Hachiga;M. Kumada
中科院分区：
文献类型：
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作者：
N. Furuichi;T. Hachiga;M. Kumada
使用多点 LDV 同时测量二维向后阶梯流的分离剪切层和再附着区域的时空速度场。本文的目的是利用空间和时间相关性以及条件平均来通过实验阐明该流场的大尺度结构的结构。从速度脉动相关性的结果来看，涡旋脱落从分离剪切层到再附着区域的运动路径呈现出两种模式，即运动到靠近壁面区域或运动到再附着区域台阶高度的中间。特别是，当它在分离的剪切层中变大时，它会移动到壁区域附近。此外，与再附着现象有关的湍流通过再循环流从再附着区域传递到分离的剪切层。根据这些湍流传输，提出了一种自激运动的大尺度波动模型。
Measurements of spatio–temporal velocity fields at the separated shear layer and reattachment region of a two-dimensional backward-facing step flow are carried out simultaneously using a multi-point LDV. The objective of this paper is to clarify experimentally the structure of a large-scale structure of this flow field using a space and time correlation and conditional average. From the results of the correlation of the velocity fluctuation, the moving path of the vortex shedding from the separated shear layer to the reattachment region exhibits two patterns which it moves to near the wall region or the middle of the step height at the reattachment region. Especially, it moves to near the wall region when it grows larger in the separated shear layer. Moreover, the turbulence concerned with reattachment phenomenon transports from the reattachment region to a separated shear layer by recirculation flow. According to these transports of turbulence, a model for large-scale fluctuation is proposed as a self-excitation motion.