Vortex-induced vibrations of a neutrally buoyant circular cylinder near a plane wall
This paper presents an experimental study of the motions, drag force and vortex shedding patterns of an elastically mounted circular cylinder, which is held at various heights above a plane wall and is subject to vortex-induced vibration (VIV) in the transverse direction. The cylinder is neutrally b...
| Main Authors: | , , |
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| Other Authors: | |
| Format: | Journal Article |
| Language: | English |
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2013
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| Online Access: | https://hdl.handle.net/10356/103042 http://hdl.handle.net/10220/16894 |
| _version_ | 1826116889712001024 |
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| author | Hao, Zhiyong Wang, X. K. Tan, S. K. |
| author2 | School of Civil and Environmental Engineering |
| author_facet | School of Civil and Environmental Engineering Hao, Zhiyong Wang, X. K. Tan, S. K. |
| author_sort | Hao, Zhiyong |
| collection | NTU |
| description | This paper presents an experimental study of the motions, drag force and vortex shedding patterns of an elastically mounted circular cylinder, which is held at various heights above a plane wall and is subject to vortex-induced vibration (VIV) in the transverse direction. The cylinder is neutrally buoyant with a mass ratio ⁎m=1.0 and has a low damping ratio ζ=0.0173. Effects of the gap ratio (S/D) ranged from 0.05 to 2.5 and the free-stream velocity (U) ranged from 0.15 to 0.65 m/s (corresponding to 3000≤Re≤13 000, and 1.53≤⁎U≤6.62) are examined. The flow around the cylinder has been measured using particle image velocimetry (PIV), in conjunction with direct measurements of the dynamic drag force on the cylinder using a piezoelectric load cell. Results of the vibrating cylinder under unbounded (or free-standing) condition, as well as those of a near-wall stationary cylinder at the same gap ratios, are also provided. For the free-standing cylinder, the transition from the initial branch to the upper branch is characterized by a switch of vortex pattern from the classical 2S mode to the newly-discovered 2PO mode by Morse and Williamson (2009). The nearby wall not only affects the amplitude and frequency of vibration, but also leads to non-linearities in the cylinder response as evidenced by the presence of super-harmonics in the drag force spectrum. In contrast to the case of a stationary cylinder that vortex shedding is suppressed below a critical gap ratio (S/D≈0.3), the elastically mounted cylinder always vibrates even at the smallest gap ratio S/D=0.05. Due to the proximity of the plane wall, the vortices shed from the vibrating cylinder that would otherwise be in a double-sided vortex street pattern (either 2S or 2PO mode) under free-standing condition are arranged into a single-sided pattern. |
| first_indexed | 2024-10-01T04:18:49Z |
| format | Journal Article |
| id | ntu-10356/103042 |
| institution | Nanyang Technological University |
| language | English |
| last_indexed | 2024-10-01T04:18:49Z |
| publishDate | 2013 |
| record_format | dspace |
| spelling | ntu-10356/1030422020-03-07T11:43:45Z Vortex-induced vibrations of a neutrally buoyant circular cylinder near a plane wall Hao, Zhiyong Wang, X. K. Tan, S. K. School of Civil and Environmental Engineering Maritime Research Centre Nanyang Environment and Water Research Institute DRNTU::Engineering::Civil engineering This paper presents an experimental study of the motions, drag force and vortex shedding patterns of an elastically mounted circular cylinder, which is held at various heights above a plane wall and is subject to vortex-induced vibration (VIV) in the transverse direction. The cylinder is neutrally buoyant with a mass ratio ⁎m=1.0 and has a low damping ratio ζ=0.0173. Effects of the gap ratio (S/D) ranged from 0.05 to 2.5 and the free-stream velocity (U) ranged from 0.15 to 0.65 m/s (corresponding to 3000≤Re≤13 000, and 1.53≤⁎U≤6.62) are examined. The flow around the cylinder has been measured using particle image velocimetry (PIV), in conjunction with direct measurements of the dynamic drag force on the cylinder using a piezoelectric load cell. Results of the vibrating cylinder under unbounded (or free-standing) condition, as well as those of a near-wall stationary cylinder at the same gap ratios, are also provided. For the free-standing cylinder, the transition from the initial branch to the upper branch is characterized by a switch of vortex pattern from the classical 2S mode to the newly-discovered 2PO mode by Morse and Williamson (2009). The nearby wall not only affects the amplitude and frequency of vibration, but also leads to non-linearities in the cylinder response as evidenced by the presence of super-harmonics in the drag force spectrum. In contrast to the case of a stationary cylinder that vortex shedding is suppressed below a critical gap ratio (S/D≈0.3), the elastically mounted cylinder always vibrates even at the smallest gap ratio S/D=0.05. Due to the proximity of the plane wall, the vortices shed from the vibrating cylinder that would otherwise be in a double-sided vortex street pattern (either 2S or 2PO mode) under free-standing condition are arranged into a single-sided pattern. 2013-10-25T02:59:41Z 2019-12-06T21:04:22Z 2013-10-25T02:59:41Z 2019-12-06T21:04:22Z 2013 2013 Journal Article Wang, X. K., Hao, Z., & Tan, S. K. (2013). Vortex-induced vibrations of a neutrally buoyant circular cylinder near a plane wall. Journal of fluids and structures, 39, 188-204. 0889-9746 https://hdl.handle.net/10356/103042 http://hdl.handle.net/10220/16894 10.1016/j.jfluidstructs.2013.02.012 en Journal of fluids and structures |
| spellingShingle | DRNTU::Engineering::Civil engineering Hao, Zhiyong Wang, X. K. Tan, S. K. Vortex-induced vibrations of a neutrally buoyant circular cylinder near a plane wall |
| title | Vortex-induced vibrations of a neutrally buoyant circular cylinder near a plane wall |
| title_full | Vortex-induced vibrations of a neutrally buoyant circular cylinder near a plane wall |
| title_fullStr | Vortex-induced vibrations of a neutrally buoyant circular cylinder near a plane wall |
| title_full_unstemmed | Vortex-induced vibrations of a neutrally buoyant circular cylinder near a plane wall |
| title_short | Vortex-induced vibrations of a neutrally buoyant circular cylinder near a plane wall |
| title_sort | vortex induced vibrations of a neutrally buoyant circular cylinder near a plane wall |
| topic | DRNTU::Engineering::Civil engineering |
| url | https://hdl.handle.net/10356/103042 http://hdl.handle.net/10220/16894 |
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