The flow past a cactus-inspired grooved cylinder
The flow past a cactus-inspired grooved cylinder
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DOI：
10.1007/s00348-013-1464-z
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发表时间：
2013-02
影响因子：
2.4
通讯作者：
Adnan M. El-Makdah;G. F. Oweis
中科院分区：
文献类型：
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作者：
Adnan M. El-Makdah;G. F. Oweis
巨大的圆柱形仙人掌植物的星形横截面被认为在空气动力学上有利于防止强风倾倒。利用粒子图像测速技术研究了具有8个纵向沟槽的仙人掌圆柱模型在生物学相关雷诺数为50 × 103 ~ 170 × 103范围内的表面沟槽内和直接尾迹中的流动细节。尾流进行了分析，并与类似尺寸的圆柱体。在试验的最低Re下，两种几何形状的尾流相似。在较高Re下，仙人掌尾迹表现出上级特性，从平均速度和湍流速度来看，这表明流动机制是独立的。表面凹槽内的流动揭示了反向旋转的滚子，而几何脊用作已知有助于表面流动附着的涡流发生器。最后，一个简单的分析，描述了恢复，定性，某些随时间变化的流动特征，从随机采集的PIV实现。
The star-shaped cross section of giant cylindrical cactus plants is thought to be aerodynamically favorable for protection against toppling by strong winds. Particle image velocimetry is used to investigate the flow details within the surface grooves and in the immediate wake of a cactus-inspired model cylinder with eight longitudinal grooves, at biologically relevant Reynolds numbers between 50 × 103and 170 × 103. The wake flow is analyzed and compared to a similarly sized circular cylinder. At the lowest Re tested, the wakes from the two geometries are similar. At higherRe, the cactus wake exhibits superior behavior as seen from the mean and turbulent velocities, suggesting that the flow mechanisms areRedependent. The flow within the surface grooves reveals counter rotating rollers, while the geometrical ridges act as vortex generators known to help with the surface flow attachment. Lastly, a simplistic analysis is described to recover, qualitatively, certain time-dependent flow features from the randomly acquired PIV realizations.