Vibration of Cylindrical Structures Induced by Axial Flow

In this paper we consider the vibration of flexible cylinders, isolated or in clusters, induced by axial flow. It has been shown that for the range of flow velocities and other parameters pertaining to industrial systems, the effect of purely axial, steady, and uniform flow is to damp free motions of the cylinders. Nevertheless, departures from such ideal flow conditions induce small-amplitude vibration, which is the subject of this paper. The underlying mechanism of the vibration is examined, as well as the means for its prediction. These latter are either empirical or analytical (generally semiempirical); the analytical methods are further classified into three categories accordingly as they postulate the vibration to be forced, parametric, or self-excited. The measure of success achieved in predicting the vibration amplitude is discussed, and possible reasons to account for its being generally poor.