| 陈槐,钟强,李丹勋,王兴奎.雷诺数对空腔水流时均结构的影响[J].水利学报,2014,45(1): |
| 雷诺数对空腔水流时均结构的影响 |
| Influence of Reynolds number on time-mean cavity flow structures |
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| DOI： |
| 中文关键词: 空腔流动 时均涡旋 雷诺应力 雷诺数 PIV |
| 英文关键词: cavity flow time-averaged vortex Reynolds stress Reynolds number PIV |
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| 中文摘要: |
| 利用PIV（粒子图像测速）测得的不同雷诺数下空腔中垂面的流场序列，分析来流条件对空腔流场涡旋结构及掺混特性的影响。时均流场中存在两个不同大小、旋转方向相反的涡旋。随着雷诺数增大，大涡旋发展壮大并最终受制于固壁边界，小涡旋受大涡旋压迫而减小，两者最终稳定的雷诺数都接近2000，大小涡旋稳定半径分别为0.83D、0.13D（空腔深度）。雷诺数的增大导致来流剪切层与空腔冲撞区域从空腔下游角点延伸至凹腔内部，其中，掺混程度相对较小的区域，面积随雷诺数增加而快速增大；掺混程度相对剧烈的区域，范围会较快趋于稳定。剪切层与空腔下游边壁的冲撞作用，决定了空腔的掺混特性，并使得雷诺应力高值区与时均大涡旋间的形态存在较好的相关性。 |
| 英文摘要: |
| This paper presents an experimental study of the influence of Reynolds number （Re） on flow structures in cavity flows， with focus on the variation of time-averaged vortexes and the spatial distribution of Reynolds stress. Velocity vectors in the mid-perpendicular section of the cavity were measured at various Re （240-4190） with particle image velocimetry （PIV）. The results show that at aspect ratio of 4 there exist two counter-rotating vortexes in the cavity which stabilize at Re=2000. The size of the counter-clockwise vortex is close to boundary dimension with a radius of 0.83D （cavity depth）. The clockwise vortex is much smaller with a radius of 0.13D. The increase in Re leads to enhanced impinging at the trailing corner and broadened mixing range in the cavity. Good correlation has been found between Reynolds stress and the counter-clockwise vortex. A model is proposed to interpret such correlation and the generation process of vortexes. |
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