| 纵向沟槽壁面湍流边界层内类开尔文-亥姆霍兹涡结构的流动显示 |
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| 引用本文： | 杨绍琼,崔宏昭,姜楠.纵向沟槽壁面湍流边界层内类开尔文-亥姆霍兹涡结构的流动显示[J].力学学报,2015,47(3):529-533. |
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| 作者姓名： | 杨绍琼 崔宏昭 姜楠 |
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| 作者单位： | 1.诺丁汉大学工程学院, 英国诺丁汉NG7 2RD;2.天津大学机械工程学院力学系, 天津300072;3.天津市现代工程力学重点实验室, 天津300072 |
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| 基金项目： | 国家自然科学基金(11272233,11332006,11411130150),国家留学基金(201306250092)和天津大学优秀博士学位论文基金资助项目. |
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| 摘 要： | 纵向沟槽壁面的湍流边界层,当沟槽的脊-脊内尺度无量纲展向间距s+ 在一定范围内,与光滑壁面湍流边界层相比,具有减阻效应;并在s+ 约为17 个黏性长度单位时减阻效果达到最优,之后其减阻趋弱,直至增阻;其原因可能是沟槽壁面湍流边界层由于“开尔文-亥姆霍兹” 不稳定性而产生的一种“类开尔文-亥姆霍兹”展向涡结构. 实验采用烟雾流动显示技术,首次在风洞中显示了这种“类开尔文-亥姆霍兹” 展向涡结构,确认了其存在性,并在概念上简单勾勒了其结构模型.
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| 关 键 词： | 湍流边界层 开尔文-亥姆霍兹不稳定性 “类开尔文-亥姆霍兹”涡 沟槽 流动显示 |
| 收稿时间： | 2015-01-24 |
| 修稿时间： | 2015-02-12 |
FLOW VISUALIZATIONS ON KELVIN-HELMHOLTZ-LIKE ROLLER STRUCTURES IN TURBULENT BOUNDARY LAYER OVER RIBLETS |
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| Yang Shaoqiong
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Kwing-So Choi
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Jiang Nan.FLOW VISUALIZATIONS ON KELVIN-HELMHOLTZ-LIKE ROLLER STRUCTURES IN TURBULENT BOUNDARY LAYER OVER RIBLETS[J].chinese journal of theoretical and applied mechanics,2015,47(3):529-533. |
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| Authors: | Yang Shaoqiong Kwing-So Choi Jiang Nan |
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| Institution: | 1.Faculty of Engineering, University of Nottingham, University Park, Nottingham NG7 2RD, UK;2.Department of Mechanics, School of Mechanical Engineering, Tianjin University, Tianjin 300072, China;3.Tianjin Key Laboratory of Modern Engineering Mechanics, Tianjin 300072, China |
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| Abstract: | Riblets perform a drag-reducing effect on the turbulent boundary layers (TBLs) in a certain range of their peak-to-peak spacings, s+. However, the drag reduction produced by the riblets breaks down after s+ increasing beyond its optimum value, and eventually the drag reduction becomes an increase case. García-Mayoral and Jiménez (2011) believed that the breakdown is due to the onset of a Kelvin-Helmholtz instability in the TBL over riblets, which introduces a kind of Kelvin-Helmholtz-like roller structures. In the present study, these spanwise rollers, for the first time in experiments, were clearly observed by the smoke flow visualization technique. And their conceptual model was outlined lastly as well. |
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| Keywords: | turbulent boundary layer Kelvin-Helmholtz instability Kelvin-Helmholtz-like rollers riblets flow visualization |
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