Numerical Characterization of the Area Perturbation and Timelag for a Vibrating Tube Subjected to Cross-Flow

Abstract

Fluidelastic instability can have disastrous effects on the integrity of steam generators. Over the last five decades there has been a great deal of research done in an attempt to understand this phenomenon. These efforts have resulted in several theoretical models and design guidelines. The semi-analytical model of fluidelastic instability initially developed by Lever and Weaver is based on a single tube in a channel flow. The mechanism responsible for instability was found to be one of flow redistribution. While previous studies have been able to characterize the pressure and velocity within a tube bundle, the behaviour of the area of the channel has not yet been fully investigated. The current study aims to characterize the area of the channel surrounding the tube. Reynolds Averaged Navier Stokes (RANS) equations are cast in an Arbitrary Lagrangian Eulerian (ALE) form and are used to compute the flow conditions in a rigid tube bundle due to a single flexible tube vibrating in the transverse direction. The properties of the velocity field are used to determine the channel boundaries. Properties of the channel area such as area perturbation, mean area, and area phase are investigated for various reduced flow velocities. Dynamic simulations are conducted to determine the impact on the stability threshold for transverse fluid force cases using a mass damping parameter range of 10–200.