| 有限长正方形棱柱绕流的双稳态现象 |
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| 引用本文： | 王汉封,徐萌霞.有限长正方形棱柱绕流的双稳态现象[J].力学与实践,2013,35(3):46-50. |
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| 作者姓名： | 王汉封 徐萌霞 |
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| 作者单位： | 1. 中南大学土木工程学院, 长沙 410075;
2. 高速铁路建造技术国家工程试验室, 长沙 410075 |
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| 基金项目： | 国家自然科学基金资助项目 |
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| 摘 要： | 运用大涡模拟(large eddy simulation, LES) 方法对有限长正方形棱柱绕流进行了研究. 棱柱高宽比为5,一端固定于平板上,另一端为自由端. 平板表面边界层厚度可忽略不计. 基于自由流速度和棱柱宽度的雷诺数为3 900. 由计算结果发现,有限长棱柱的尾流在自由端后下扫流的作用下具有显著的三维性. 尾流中会交替出现两种典型的流动状态:一种是柱体两侧所脱落的涡在尾流中形成类似卡门涡街的交错排列状态;另一种是柱体尾流中涡团对称分布且无明显的周期性. 两种典型流动状态的交替出现,对有限长棱柱气动力特性有直接的影响.
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| 关 键 词： | 有限长钝体 尾流 双稳态 气动力 大涡模拟 |
| 收稿时间： | 2013-03-21 |
BISTABLE PHENOMENON OF THE FLOW AROUND A FINITE-LENGTH SQUARE PRISM |
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| WANG Hanfeng,XU Mengxia.BISTABLE PHENOMENON OF THE FLOW AROUND A FINITE-LENGTH SQUARE PRISM[J].Mechanics and Engineering,2013,35(3):46-50. |
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| Authors: | WANG Hanfeng XU Mengxia |
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| Institution: | 1. School of Civil Engineering, Central South University, Changsha 410075, China;
2. National Engineering Laboratory for High-Speed Railway Construction, Changsha 410075, China |
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| Abstract: | The flow around a finite-length square prism is numerically investigated using the LES (large eddy simulation). The aspect ratio of the prism is 5. The prism is mounted on a flat wall, with one end free. The thickness of the boundary layer on the flat wall is very small to be negligible. The Reynolds number based on the free-stream oncoming velocity and the prism width is 3 900. Based on the simulation results, it is found that the near wake is highly three dimensional under the effects of the free-end downwash flow. Two typical flow states were observed in the near wake: first, the spanwise vortices are staggered arranged similar to the Karman vortex street; second, the spanwise vortices are quasi-symmetrically arranged without obvious periodicity. These two typical states occur alternately, which affects the aerodynamic forces on the prism. |
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| Keywords: | finite-length bluff body wake bistable phenomenon aerodynamic force LES (large eddy simulation |
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