| 射流卷吸边界层内相干结构的实验研究 |
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| 引用本文： | 周雷,周骛,郭延昂,蔡小舒. 射流卷吸边界层内相干结构的实验研究[J]. 化工学报, 2019, 70(7): 2520-2527. DOI: 10.11949/0438-1157.20190048 |
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| 作者姓名： | 周雷 周骛 郭延昂 蔡小舒 |
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| 作者单位： | 上海理工大学颗粒与两相流测量研究所，上海 200093 |
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| 基金项目： | 国家自然科学基金项目（51327803，51576130） |
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| 摘 要： | 在轴对称水射流实验台上，采用单帧长曝光图像法，测量了出口Reynolds数在1849~2509范围内的卷吸边界层内流场结构。发现在流向距离L=2D~3.5D，径向距离H=D~1.25D的区域内，流场中吞噬作用和侵蚀作用两种卷吸模式交替出现。分析得到，当Re>1915时，吞噬作用所占的比例随着Re的增大而增大，当Re>2311之后，Reynolds数对该结构发生概率的影响降低；通过快速傅里叶变换得到该相干结构发生的频率在10～19Hz之间；吞噬作用发生的同时在流场中观测到一些特殊涡结构。同时采用运动单帧长曝光图像法对射流流场进行拉格朗日法观测，发现射流流场中的涡结构一般存在于湍流与非湍流界面附近。
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| 关 键 词： | 单帧长曝光 运动单帧长曝光 卷吸边界层 射流 湍流与非湍流界面 涡结构 |
| 收稿时间： | 2019-01-14 |
| 修稿时间： | 2019-04-26 |
Experimental studies on coherent structures in jet entrainment boundary layers |
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| Lei ZHOU,Wu ZHOU,Yan ang GUO,Xiaoshu CAI. Experimental studies on coherent structures in jet entrainment boundary layers[J]. Journal of Chemical Industry and Engineering(China), 2019, 70(7): 2520-2527. DOI: 10.11949/0438-1157.20190048 |
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| Authors: | Lei ZHOU Wu ZHOU Yan ang GUO Xiaoshu CAI |
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| Affiliation: | Institute of Particle and Two-phase Flow Measurement, University of Shanghai for Science and Technology, Shanghai 200093, China |
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| Abstract: | On the axis-symmetric water jet test bench, the flow field structure in the entrainment boundary layer with the Reynolds number in the range of 1849－2509 was measured by the single-frame long exposure image method. It is found that engulfing and nibbling entrainment model occur intermittently with time, in the region of L=2D－3.5D streamwise and H=D－1.25D radial direction. It concludes from analyzing that the occurrence probability of engulfing increases with Reynolds number when Re>1915, the influence of Reynolds number on the occurrence probability of this structure decreases when Re>2311.The occurrence frequency of this coherent structure obtained by fast Fourier transform is between 10 Hz and 19 Hz. Special vortex structures were observed in the flow field during the occurrence of engulfing. The jet flow field are measured using moving single frame long exposure image method in Lagrangian coordinate system, and it is found that the vortex structure generally existed near the interface of turbulent regions and non-turbulent regions. |
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| Keywords: | single frame long exposure move single frame long exposure entrainment layers jet turbulent and non-turbulent interface vortex structures |
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