Non-intrusive measurements of a blunt circular cylinder in a magnetic suspension wind tunnel
Non-intrusive measurements of a blunt circular cylinder in a magnetic suspension wind tunnel
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磁悬浮风洞中钝圆柱体的非侵入式测量
DOI：
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发表时间：
2008
期刊：
影响因子：
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通讯作者：
T. Kunimasu
中科院分区：
文献类型：
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作者：
H. Sawada;H. Higuchi;H. Kato;T. Kunimasu
利用JAXA 60 cm磁悬浮天平系统（MSBS）、数字遥测系统和粒子图像测速仪（PIV），在雷诺数为100，000（基于圆柱直径）的条件下，测量了轴向圆柱上的气动力和底部压力以及圆柱周围的流场。这些模型由MSBS悬挂，没有任何支撑干扰。它们的细度比在1.27 ~ 1.79之间。在垂直于模型轴线的尾流横截面上测量了流场，并在与模型轴线平行的截面上测量了流场。测试结果表明，这三种器械可以同时使用。在JAXA 60 cm MSBS上，估计的小于约15 Hz的非定常气动力可以成功地评估。阻力波动功率谱中的峰值在约1.5 Hz处观察到（Strouhal数约为0.012），该峰值对应于底部压力波动功率谱中的峰值，但在侧力谱中不存在。这被认为是由回流区的轴向振荡引起的。主底压脉动频率的Strouhal数为0.34，对应于大尺度的旋涡脱落。在垂直于圆柱轴线的尾迹非定常横截面流场中观察到大量纵向涡，它们在流场中广泛地运动。轴向圆柱体的任何支架都会干扰流场进行这样的观察。
Aerodynamic force and base pressure on axial cylinders as well as flow fields around them were measured at 100,000 of Reynolds number based on their diameter with the JAXA 60cm magnetic suspension and balance system (MSBS), a digital telemeter system, and a particle image velocimetry (PIV). The models were suspended by the MSBS without any support interference. The fineness ratio of them ranged from 1.27 to 1.79. The flow fields were measured in the cross section of the wake perpendicular to the model axis and were also measured in the parallel section including model axis. The test results showed that these three devices could be used concurrently. At the JAXA 60cm MSBS, estimated unsteady aerodynamic force less than about 15Hz could be evaluated successfully. A peak in the power spectrum of the drag fluctuations was observed at about 1.5 Hz (Strouhal number of approximately 0.012) which corresponded to a peak in the power spectrum of the base pressure fluctuations, but absent in the side force spectrum. This is considered to be caused by the axial oscillation of the recirculation region. The Strouhal number of the main base pressure fluctuating frequency was 0.34 which corresponded to large scale vortex shedding. Numerous longitudinal vortices were observed in the unsteady cross sectional flow field of the wake perpendicular to the cylinder axis and they moved widely in the field. Any sting mount of an axial cylinder would have interfered with the flow field to make such observations.