Abstract In the present study, we place a short splitter plate onto the upstream side of a circular cylinder to modify its incoming flow conditions and the wake-vortex patterns and to attenuate the aerodynamic forces. Wind-tunnel investigations are performed at a Reynolds number of Re = 2.66 × 10 4 . Special interests are paid to the length sensitivity of the rigid splitter plate. The 2D particle image velocimetry (PIV) technique is employed to measure the flow patterns around the natural and controlled cylinders to reveal the great modifications of the upstream plate to the cylinder flow. Except for PIV tests, sectional pressure measurements are also conducted to obtain the pressure distribution around the cylinder surface so as to estimate the aerodynamic forces, i.e. drag and lift forces of the natural and controlled cylinders. Results of the surface-pressure measurement demonstrate clearly the control effectiveness and the surrounding flow topologies obtained by PIV system help to uncover the mechanism of the passive upstream-plate control.

中文翻译：

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带有上游分流板的固定圆柱体的流动特性：关于板长敏感性

摘要 在本研究中，我们将一个短分流板放置在圆柱体的上游侧，以改变其传入流动条件和尾涡模式并减弱空气动力。风洞调查以雷诺数 Re = 2.66 × 10 4 进行。特别关注刚性分隔板的长度敏感性。2D 粒子图像测速 (PIV) 技术用于测量自然和受控圆柱体周围的流动模式，以揭示上游板对圆柱体流动的巨大改变。除了 PIV 测试外，还进行截面压力测量以获得气缸表面周围的压力分布，从而估算空气动力，即自然和受控气缸的阻力和升力。