Theoretical Analysis of Nonlinear Effects on the Flutter and Divergence of a Tube Conveying Fluid

摘要

A theoretical model capable of describing the flutter and divergence of a tube conveying high velocity fluid is developed in this study. The nonlinear effect due to tension induced by bending is considered along with other linear forces. The partial differential equations by Galerkin's method and the time histories of the tube motion are evaluated numerically. Numerical results for the thresholds of flutter instability and the mode shapes of a cantilevered tube are in good agreement with those obtained theoretically and experimentally be other investigators. (1) A static or divergence instability occurs at a certain critical fluid velocity if the tube is simply supported at both ends. At higher fluid velocity, the tube becomes dynamically unstable. The limit cycle oscillations of the cantilever tube and the characteristics of the simply supported tube motion predicted by the present nonlinear analysis remain to be verified quantitatively be experiment.