Pipeline Flow Of The Traveling Wave Method Of Coupled Vibration

The analysis of the fluid-structure interaction of pipes conveying fluid has wide engineering background and is of important theoretical significance and research worthiness. The pipe system is chosen as the investigative object and the influence of fluid-structure interaction (FSI) is considered in this dissertation. Based on the idea that the vibration of the pipe is one of the propagating waves, the traveling wave method is used to investigate the dynamic characters of the straight and curved pipe conveying fluid .As to the straight pipe with uniform diameter, the wave-guide equation is deduced by solving the classical differential equations of the pipe. The scattering model of the FSI system is constructed by considering the boundary conditions of the nodes at adjacent elements. Numerical results are compared to the results by former researchers, and it shows that the results by the traveling wave method are correct and it has much higher accuracy than the finite element method. The influence of the Possion ratio and the boundary conditions are discussed. At the same time, the average velocity of the fluid is studied to determine its influence on the pipe's stability. The support condition is also discussed to control the vibration of the pipe.On the basis of the analysis of the straight pipes, two different methods are put forward to study the dynamic characters of the curved pipe. One method is to discretize the curved pipe into many short straight elements. The rigidity factor is introduced to correct the flexural stiffness and the coordinate transform matrix is constructed to model the pipe bend. So the hybrid model method of straight-curved pipe is realized. The other method is to construct the curved pipe directly. According to the dynamic differential equation of the curved beam and the fluid, the wave-guide equation considering FSI is deduced. The second method is much simpler and more convenient than the first one, and it reduces the complexity of the problem.The experimental analysis of a multi-span straight pipe is demonstrated to validate the feasibility of the traveling wave method. The experimental results show that the traveling wave method is effective and it has higher precision than the finite element method.