The effects of free surface and end cell on flow around a finite circular cylinder with low aspect ratio
The effects of free surface and end cell on flow around a finite circular cylinder with low aspect ratio
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DOI：
10.1007/s00773-015-0338-x
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发表时间：
2016-03
影响因子：
2.6
通讯作者：
H. Fukuoka;S. Hirabayashi;Hideyuki Suzuki
中科院分区：
文献类型：
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作者：
H. Fukuoka;S. Hirabayashi;Hideyuki Suzuki
涡激运动是小展弦比浮体的一种振荡现象。利用粒子图像测速技术和水动力测量技术，对自由表面和端胞对有限长固定圆柱绕流的影响进行了基本的唯象研究。实验结果表明，圆柱尾流不仅受到端部网格的影响，而且还受到自由表面的影响。爆破和回流是从端部单元产生的，它们的影响被自由表面所中止。水动力测量结果显示了雷诺数、弗劳德数和浮体长宽比对水动力的影响。水动力系数的波动分量随雷诺数、佛汝德数和展弦比的增大而减小。另一方面，平均阻力系数随弗劳德数的增加而增加，随展弦比的增加而减小。并与实验中观察到的流动结构进行了比较，讨论了对这些结果的解释。此外，还发现雷诺数对平均阻力系数的影响在不同的展弦比下是不同的。对这一现象提出了一种可能的解释。
Vortex-induced motion is an oscillatory phenomenon which occurs to a floating body with low aspect ratio. The basic phenomenological study about the effects of free surface and end cell on flow around a finite fixed circular cylinder was investigated in this study using particle image velocimetry and hydrodynamic force measurement. It was found from the former experiment that the wake of the cylinder is influenced by the both end cell and free surface. Blowup and back flow are generated from the end cell, and their effects are suspended by free surface. The result of hydrodynamic force measurement showed the effect of Reynolds number, Froude number, and the aspect ratio of the floating body on the hydrodynamic force. Fluctuating components of hydrodynamic coefficients decrease for increasing Reynolds number, Froude number, and the aspect ratio. On the other hand, the mean drag coefficient increases as Froude number increases and decreases as the aspect ratio increases. The interpretation to these results was discussed in comparison with flow structures observed in the experiment. In addition, it was found that the effect of Reynolds number on the mean drag coefficient changes at different aspect ratios. A possible interpretation to this phenomenon was proposed.