摘要
灵活圆形的柱体的导致流动的颤动(FIV ) 上的集体比率的效果试验性地在一辆拖引的坦克被调查。分别地，有 7.9 公里和 4.8 公里的外部、内部的直径的一个 Tygon 试管为学习被采用。试管被连接到一辆马车并且从休息拖引到一稳定在慢下来在 1.6 m 的距离上再休息在前加快 m/s 到 1.6 仍然流水。雷纳兹数字基于柱体，外部直径是 80013,000，并且减少的速度(柱体天赋频率使正常化的速度和外部直径) 从 2 ～ 25 跨越了。当连接时，柱体在 11 N 的轴的虚荣下面从 420 公里被伸长到 460 公里。把伸长的长度基于柱体，方面比率(到外部直径的柱体长度的比率) 作为 58 被计算。三集体比率(柱体的比率结构的质量到代替的液体质量， m *) 被分别地用空气，水，和合金粉末(nickel-chromium-boron 矩阵合金) 填满柱体内部 0.7， 1.0，和 3.4 决定。一个光方法为反应大小被采用。多频率颤动在两个被观察同轴(IL ) 并且跨流动(CF ) 回答；在高级雷纳兹数字，颤动模式直到 3 <sup > rd </sup> 在 CF 反应被识别。模式转变被发现为最高测试的集体比率在更低的减少的速度发生。颤动振幅和频率关于减少的速度被确定并且表示。一个重要减少的颤动振幅与增加集体比率在 IL 反应被发现，并且仅仅起始、上面的分支在 IL 和 CF 反应振幅存在。规范的反应频率被揭示线性地关于减少的速度增加，并且为线性关系的斜坡被发现为测试的三格相同。
The effect of the mass ratio on the flow-induced vibration （FIV） of a flexible circular cylinder is experimentally investigated in a towing tank. A Tygon tube with outer and inner diameters of 7.9 mm and 4.8 mm, respectively, was employed for the study. The tube was connected to a carriage and towed from rest to a steady speed up to 1.6 m/s before slowing down to rest again over a distance of 1.6 m in still water. Reynolds number based on the cylinder＇s outer diameter was 800-13,000, and the reduced velocity （velocity normalized by the cylinder＇s natural frequency and outer diameter） spanned from 2 to 25. When connected, the cylinder was elongated from 420 mm to 460 mm under an axial pre-tension of 11 N. Based on the cylinder＇s elongated length, the aspect ratio （ratio of the cylinder＇s length to outer diameter） was calculated as 58. Three mass ratios （ratio of the cylinder＇s structural mass to displaced fluid mass, m＊） of 0.7, 1.0, and 3.4 were determined by filling the cylinder＇s interior with air, water, and alloy powder （nickel-chromium-boron matrix alloy）, respectively. An optical method was adopted for response measurements. Multi-frequency vibrations were observed in both in-line （IL） and cross-flow （CF） responses; at high Reynolds number, vibration modes up to the 3rd one were identified in the CF response. The mode transition was found to occur at a lower reduced velocity for the highest tested mass ratio. The vibration amplitude and frequency were quantified and expressed with respect to the reduced velocity. A significant reduced vibration amplitude was found in the IL response with increasing mass ratios, and only initial and upper branches existed in the IL and CF response amplitudes. The normalized response frequencies were revealed to linearly increase with respect to the reduced velocity, and slopes for linear relations were found to be identical for the three cases tested.
