Overview of Vibro-Impact Dynamics of Pipes Conveying Fluids and the Problem of Fluid-Elastic Instability Available to Purchase

This paper presents an overview of vibro-impact dynamics of pipes conveying fluid and the fluid-elastic instability under conditions of turbulence and nonlinearities in nuclear power plants. Different types of modeling, dynamic analysis and stability regimes of pipes conveying fluid restrained by elastic or inelastic barriers are described. The main results reported in the literature will be discussed. The sources of discrepancies in the results will be identified. The main source is primarily the inaccuracy of analytical modeling of the pipe dynamics and impact interaction. The occurrence of flow-induced vibration fretting wear in process equipment such as heat exchangers and steam generators accounts for the majority of failures due to vibration. The fretting wear problem will be first described. This is followed by discussing the computational algorithms used to predict some aspects of vibro-impact dynamics such as the fluid-elastic instability of a tube array by cross flow. Fretting wear prediction requires nonlinear computations of the tube dynamics in which proper modeling of the fluid forcing function plays an important role. Some experimental results pertaining to the vibro-impact motion due to tube-support gaps are discussed with an emphasis on the remote identification of impact forces.