Experimental study of the column shape and the roughness effects on the vortex-induced motions of deep-draft semi-submersible platforms
Experimental study of the column shape and the roughness effects on the vortex-induced motions of deep-draft semi-submersible platforms
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DOI：
10.1016/j.oceaneng.2017.12.013
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发表时间：
2018-02
影响因子：
5
通讯作者：
Rodolfo T. Gonçalves;A. Fujarra;G. Rosetti;A. M. Kogishi;A. Koop
中科院分区：
文献类型：
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作者：
Rodolfo T. Gonçalves;A. Fujarra;G. Rosetti;A. M. Kogishi;A. Koop
进行了四柱不锈钢平台Vim实验，研究了表面粗糙度和柱体形状对振动诱导成形的影响。两种不同的几何形状的列进行了实验：圆角方形和圆形截面。每个模型都有相同的四个浮筒布置在一个封闭的配置。约化速度的范围是从4到25，覆盖雷诺数从7.000到80.000。测试了每个模型的三个入射角，即0 °、22.5 °和45°。对于每个模型，测试了三种不同水平的粗糙度。关于粗糙度的影响，结果似乎证实了两个方面：由分离点附近的圆角的圆角方柱和粗糙度对圆柱的边界层的影响所发挥的重要作用。关于圆柱形状的影响，结果表明，标题对SS的Vim强烈依赖于圆柱形状的影响。特征运动周期支持横向运动的共振行为和锁定范围内的偏航运动。垂荡、滚转和偏航运动不影响水平面内的Vim行为，并且认为它们的振幅不相关。
Experiments regarding the VIM of SS platforms with four columns were carried out to investigate the effects of the surface roughness and the column shape. Two different geometry of columns were experimented: rounded-square and circular-cross sections. Each model had the same arrangement of four pontoons in a closed configuration. The range of reduced velocity was from 4 up to 25 covering Reynolds numbers from 7.000 to 80.000. Three angles of incidences for each model were tested, namely 0, 22.5 and 45°. For each model, three different levels of roughness were tested. Regarding roughness effects the results seem to confirm two aspects: the important role played by the separation point near the rounded corners of the rounded-square columns and the roughness effect on the boundary layers of the circular columns. Regarding the effect of the column shape, the results indicated that the heading effects on the VIM of SS strongly depend on the column shape. The characteristic motion periods upheld the resonance behavior for the motions in the transverse direction and yaw motions for the lock-in range. Heave, roll and yaw motions did not impact the VIM behavior in the horizontal plane, and their amplitudes were not considered relevant.