Research on Fluid Elasticity in Space Flight Vehicle.

众所周知，航天飞行器液体燃料管道等输送流体的薄壁弹性通道，由于流体压力与通道壁弹性变形之间的耦合作用，表现出非常复杂的静态和动态现象，包括自激振荡。许多理论和实验研究都对流道的这种特性进行了研究。不仅在航天飞行器中，流体输送通道在化工厂、原子能发电站和医疗机构中也有广泛的应用。然而，关于槽壁变形与槽内流体压力之间的关系，目前尚无可靠的基础数据。因此，在本研究的实验部分，我们建立了一个二维流道，沿着流道测量流道壁上若干点处的流动压力。通道壁面的一侧可以通过外部活塞静态或谐波移动，而另一侧壁面是刚性和固定的。在流量固定的情况下，对压力进行了测量。在一维流道分析的基础上进行了数值计算，并与实测结果进行了对比。数值计算结果与实验结果的比较为改进前人提出的解析式通道流动模型提供了有益的信息。在本研究的分析部分，从流体弹性的角度研究了受跟随力作用的双摆的稳定性和分岔问题。双摆模型是一个由喷气推进器推进的两级火箭。在这种非线性稳定性分析中，使用的是近十年来迅速发展起来的微分几何方法。充分阐明了摆的静、动稳定特性。此外，还分析了实验中观察到的输液通道的非周期运动具有混沌特性。少

It is well-known that thin-walled elastic channel conveying fluid, such as liquid fuel pipings of space vehicles, show very complicated static and dynamic phenomena, including self-excited oscillation, due to the coupling between the fluid pressure and the elastic deformation of the channel walls. Many theoretical and experimental studies have been carried out to investigate such behavior of the flow-channel. Not only in the space vehicles, the fluid-conveying channels have many applications in chemical plants, atomic energy power stations and medical treatments. There are, however, no reliable fundamental data on the relation between the wall deformation and the fluid pressure along the channel.In the experimental part of the present study, therefore, a two- dimensional flow channel was built to measure along the channel the flow pressure at a number of points on the channel wall. A one-side of the channel walls can statically or harmonically be moved by an external piston, while the … More other wall is rigid and fixed. Measurement on the pressure was made with the flow rate being fixed. Numerical calculations based on a one-dimensional flow channel analysis was performed to compare with measured results on the relation between the fluid pressure and the flow rate. Comparison between the numerical and experimental results provides useful information for improving the previous analytical channel- flow model proposed by the present researchers.In the analytical part of this study, stability and bifurcation of a double pendulum subjected to a follower force was examined from a view point of fluid elasticity. The double pendulum models a two-staged rocket propelled by a jet thruster. In this nonlinear stability analysis, used was a differential geometrical approach which has rapidly developed during the last decade. The static and dynamic stability characteristics of the pendulum have fully been clarified. In addition, aperiodic motions of the fluid-conveying channel observed in experiments have been analyzed to possess chaotic characteristics. Less