Full
Outline
Buoyancy elements are primarily used to provide additional buoyancy to improve the tension distribution along the risers. Risers covered with buoyancy elements exhibit more complex fluid–structure interaction phenomena under ocean currents, and the current understanding of their hydrodynamic characteristics remains limited. This study conducted stationary towing tests on a rigid riser model covered with buoyancy elements. Based on the hydrodynamic unit formed by the riser-buoyancy system, the drag and lift characteristics in uniform flow were investigated for different spacing arrangements and diameters of the buoyancy elements. The time-frequency characteristics of the cross-flow lift were further analyzed using wavelet transforms. The main conclusions are as follows: compared with a bare riser, the drag coefficient of the buoyancy element decreases to approximately 0.9 due to the low aspect ratio; when the diameter ratio of the buoyancy element to the riser reaches 3.52 and both components operate at Reynolds numbers above 105, the RMS lift coefficient of the hydrodynamic unit increases significantly, reaching up to 1.2 when the length ratio equals 1; the dominant frequency of lift on a riser covered with buoyancy elements exhibits time-varying jumps, with a wider fluctuation range than the vortex shedding frequencies of both the riser and the buoyancy element.
11
5
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |
关闭全屏
No. 86 Xueyuan South Road, Haidian District, Beijing
010-62662699(Operation and Technical Support)
qkjq@cast.org.cn
Copyright © 2025 China Association for Science and Technology. All rights reserved. For all open access content, the relevant licensing terms apply.
Sponsored by the Office of the Leading Group for Cybersecurity and Informatization of CAST, and supported by Science and Technology Review Publishing House
