The effectiveness of two-versus three-start helical strakes in suppressing VIV of flexible cylinder
The proposed paper investigates experimentally the effectiveness of strakes in suppressing the vortex-induced vibration (VIV) of a long flexible cylinder by varying the number of helix of the strakes, which differ from the previous studies that only focus on short rigid cylinder. The experiment was...
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| Format: | Conference or Workshop Item |
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2014
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| author | Lee, Kee Quen Abu, Aminuddin Muhamad, Pauziah Kato, Naomi Sahekhaini, Asnizah Abdullah, Hanida |
| author_facet | Lee, Kee Quen Abu, Aminuddin Muhamad, Pauziah Kato, Naomi Sahekhaini, Asnizah Abdullah, Hanida |
| author_sort | Lee, Kee Quen |
| collection | ePrints |
| description | The proposed paper investigates experimentally the effectiveness of strakes in suppressing the vortex-induced vibration (VIV) of a long flexible cylinder by varying the number of helix of the strakes, which differ from the previous studies that only focus on short rigid cylinder. The experiment was conducted in the towing tank with constant velocity under subcritical Reynolds number (0.14x104 - 1.37x104) by using a poly vinyl chloride cylinder with aspect ratio of 162. CCD cameras were installed to capture the amplitude vibration while the variation of tension was measured by using tension load-cell. The drag force coefficient and the cross-flow and in-line frequency response were obtained from the strain gauges. The purpose of the present study is to identify the main deficiency and advantage of a two-start helical strakes compare to a three-start helical strakes in reducing the VIV of a low mass ratio flexible riser. The experimental result shows that the two-start helical strakes perform well in mitigating the VIV in low reduced velocity range. However, its effectiveness in suppressing the vibration amplitude of flexible cylinder is far smaller than the three-start helical strakes. Substantial amplitude mitigation is found for the three-start helical strakes, but with significant amplification of drag at high reduced velocity, which is unfavourable. On the other hand, although the mean drag coefficient is slightly higher for the two-start helical strakes in the lock-in region, the drag force response is more consistent and independent to the velocity changes at high reduced velocity. |
| first_indexed | 2024-03-05T19:55:07Z |
| format | Conference or Workshop Item |
| id | utm.eprints-62902 |
| institution | Universiti Teknologi Malaysia - ePrints |
| last_indexed | 2024-03-05T19:55:07Z |
| publishDate | 2014 |
| record_format | dspace |
| spelling | utm.eprints-629022017-07-11T07:24:11Z http://eprints.utm.my/62902/ The effectiveness of two-versus three-start helical strakes in suppressing VIV of flexible cylinder Lee, Kee Quen Abu, Aminuddin Muhamad, Pauziah Kato, Naomi Sahekhaini, Asnizah Abdullah, Hanida T Technology The proposed paper investigates experimentally the effectiveness of strakes in suppressing the vortex-induced vibration (VIV) of a long flexible cylinder by varying the number of helix of the strakes, which differ from the previous studies that only focus on short rigid cylinder. The experiment was conducted in the towing tank with constant velocity under subcritical Reynolds number (0.14x104 - 1.37x104) by using a poly vinyl chloride cylinder with aspect ratio of 162. CCD cameras were installed to capture the amplitude vibration while the variation of tension was measured by using tension load-cell. The drag force coefficient and the cross-flow and in-line frequency response were obtained from the strain gauges. The purpose of the present study is to identify the main deficiency and advantage of a two-start helical strakes compare to a three-start helical strakes in reducing the VIV of a low mass ratio flexible riser. The experimental result shows that the two-start helical strakes perform well in mitigating the VIV in low reduced velocity range. However, its effectiveness in suppressing the vibration amplitude of flexible cylinder is far smaller than the three-start helical strakes. Substantial amplitude mitigation is found for the three-start helical strakes, but with significant amplification of drag at high reduced velocity, which is unfavourable. On the other hand, although the mean drag coefficient is slightly higher for the two-start helical strakes in the lock-in region, the drag force response is more consistent and independent to the velocity changes at high reduced velocity. 2014 Conference or Workshop Item PeerReviewed Lee, Kee Quen and Abu, Aminuddin and Muhamad, Pauziah and Kato, Naomi and Sahekhaini, Asnizah and Abdullah, Hanida (2014) The effectiveness of two-versus three-start helical strakes in suppressing VIV of flexible cylinder. In: Offshore Technology Conference Asia: Meeting the Challenges for Asia's Growth, OTC ASIA 2014, 25-28 Mac, 2014, Kuala Lumpur, Malaysia. https://pure.utm.my/en/publications/the-effectiveness-of-two-versus-three-start-helical-strakes-in-su |
| spellingShingle | T Technology Lee, Kee Quen Abu, Aminuddin Muhamad, Pauziah Kato, Naomi Sahekhaini, Asnizah Abdullah, Hanida The effectiveness of two-versus three-start helical strakes in suppressing VIV of flexible cylinder |
| title | The effectiveness of two-versus three-start helical strakes in suppressing VIV of flexible cylinder |
| title_full | The effectiveness of two-versus three-start helical strakes in suppressing VIV of flexible cylinder |
| title_fullStr | The effectiveness of two-versus three-start helical strakes in suppressing VIV of flexible cylinder |
| title_full_unstemmed | The effectiveness of two-versus three-start helical strakes in suppressing VIV of flexible cylinder |
| title_short | The effectiveness of two-versus three-start helical strakes in suppressing VIV of flexible cylinder |
| title_sort | effectiveness of two versus three start helical strakes in suppressing viv of flexible cylinder |
| topic | T Technology |
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