We consider a vertical cantilevered pipe conveying fluid, located in a container filled with the same fluid; the upper portion of the pipe is surrounded by a rigid cylindrical tube of larger diameter, thus forming an annular fluid-filled region around the pipe. Two flow configurations are investigated: (a) the fluid enters the pipe at its clamped upper end and flows downwards, discharging at its free lower end into the container; the fluid exits the container by flowing upwards in the annulus and out; (b) the reverse flow arrangement, in which the fluid enters the system at the upper end of the annulus and exits by flowing upwards in the pipe. The dynamics of the system is studied theoretically for both configurations (a) and (b) and experimentally in an in-house bench-top apparatus. The analytical models utilized, with some CFD input, are outlined, and the bench-top experiments are described. For given parameters, both theory and experiment find that the system loses stability at sufficiently high flow velocity by flutter or static divergence. Finally, theory and experiment are compared, showing reasonable to good agreement for flow configuration (a), but less than satisfactory agreement for configuration (b).

我们考虑输送流体的垂直悬臂管，它位于装满相同流体的容器中；管道的上部被直径较大的刚性圆柱管包围，从而在管道周围形成一个充满流体的环形区域。研究了两种流动配置： (a) 流体在其夹紧的上端进入管道并向下流动，在其自由下端排放到容器中；流体通过在环形空间中向上流动并流出而离开容器；(b) 逆流布置，其中流体在环空的上端进入系统并通过在管道中向上流动而离开。系统的动力学在理论上针对配置 (a) 和 (b) 进行了研究，并在内部台式设备中进行了实验研究。使用的分析模型，带有一些 CFD 输入，概述，并描述了台式实验。对于给定的参数，理论和实验都发现系统在足够高的流速下会由于颤振或静态发散而失去稳定性。最后，理论和实验进行了比较，表明流动配置 (a) 的一致性合理到良好，但配置 (b) 的一致性不太令人满意。