Investigation of the flow in a circular cavity using stereo and tomographic particle image velocimetry
Investigation of the flow in a circular cavity using stereo and tomographic particle image velocimetry
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DOI：
10.1007/s00348-008-0577-2
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发表时间：
2009-03
影响因子：
2.4
通讯作者：
C. Haigermoser;F. Scarano;M. Onorato
中科院分区：
文献类型：
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作者：
C. Haigermoser;F. Scarano;M. Onorato
通过多平面立体粒子图像测速和断层粒子图像测速 (PIV) 研究纵横比为 D/H= 2 的圆形腔上的湍流。研究的主要目的是在这些特定条件下空腔内形成的不对称流型的流动拓扑和湍流结构。在垂直对称平面上测量流场，以描述腔体中的整体再循环模式以及从分离点开始发展的湍流剪切层。在这种特定的情况下，剪切层波动被认为是由不稳定性以及传入边界层湍流的影响引起的。在腔内不同高度的几个壁平行平面上进行的额外观察可以进一步评估这种不对称状态产生的二次流动循环。观察到的流动模式由稳定的涡流组成，占据整个腔体体积并斜置于腔体内部，以便从一侧夹带外部流动，将其捕获为循环运动并将其从腔体的另一侧喷射。湍流波动的空间分布也揭示了相同的结构。断层扫描 PIV 测量返回对湍流波动的瞬时三维结构的目视检查，在研究的高度处，该湍流波动表现出低水平的相干性，并且腔内的循环流中存在稍微拉长的涡流。
The turbulent flow over a circular cavity with an aspect ratio ofD/H= 2 is investigated by multi-planar stereoscopic particle image velocimetry and with tomographic particle image velocimetry (PIV). The main aim of the study is the flow topology and the turbulent structure of the asymmetrical flow pattern that forms inside the cavity at these specific conditions. The flow field is measured in the vertical symmetry plane to describe the overall recirculation pattern in the cavity and the turbulent shear layer developing from the separation point. In this specific regime the shear layer fluctuations are recognized as those caused by instabilities together with the effect of the incoming boundary layer turbulence. Additional observations performed at several wall-parallel planes at different height inside the cavity allow to further evaluate the secondary flow circulation generated by this asymmetric regime. The observed flow pattern consists of a steady vortex, occupying the entire cavity volume and placed diagonally inside the cavity such to entrain the external flow from one side, capture it into a circulatory motion and eject it from the opposite side of the cavity. The spatial distribution of the turbulent fluctuations also reveals the same structure. The tomographic PIV measurement returns a visual inspection to the instantaneous three-dimensional structure of the turbulent fluctuations, which at the investigated height exhibit a low level of coherence with slightly elongated vortices in the recirculating flow inside the cavity.