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Please use this identifier to cite or link to this item: http://ntour.ntou.edu.tw:8080/ir/handle/987654321/37604

Title: Characteristic Flow Field behind a Square-Cylinder using Upstream Mesh Fences
Authors: Yen, S. C.;Yang, C. W
Contributors: 國立臺灣海洋大學:機械與機電工學系
Date: 2012
Issue Date: 2016-03-29T05:43:41Z
Publisher: ASME Journal of Fluids Engineering (American Society of Mechanical Engineering)
Abstract: The flow behaviors around a square cylinder were modulated using the passive mesh fence. The effects of Reynolds number (Re) and rotation angle (θ) on the square-cylinder flow fields using different turbulence intensity (TI) were also investigated. Additionally, various steel mesh fences with different mesh densities were installed between the nozzle outlet and the test-section inlet to adjust the free-stream TI. The Reynolds number and turbulence intensity used in this investigation are 3.0 × 104  ≤ Re ≤ 1.0 × 105 and 0.32% ≤ TI ≤ 0.82%. The flow fields are visualized using the surface oil-flow visualization scheme. Furthermore, the flow patterns are classified as—leading-edge bubble, separation bubble, separation, leading-edge separation, and boundary-layer attached modes. Specifically, the leading-edge bubble mode does not exist while θ and TI are low. Moreover, a hot-wire anemometer was placed in the wake to detect the vortex-shedding frequency. The experimental results indicate that Strouhal number (St) decreases with increasing the free-stream TI while TI < 0.45%. However, St approaches a constant as TI > 0.45%. Furthermore, the surface pressure was detected using a pressure scanner and the drag coefficient (CD ) was obtained using the surface-pressure profile. The experimental results also reveal that CD decreases with increasing the free-stream TI. However, the change rate of CD for TI < 0.45% exceeds that for TI > 0.45%.
URI: http://ntour.ntou.edu.tw:8080/ir/handle/987654321/37604
Appears in Collections:[機械與機電工程學系] 期刊論文

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