Stability Threshold of a Loosely Supported Triangle Tube Array Subjected to Crossflow

Abstract

Fluidelastic instability (FEI) is generally regarded as the most severe type of flow excitation mechanism. When this mechanism prevails, it causes serious damage to tube arrays in a very short period of time. In order to avoid these excessive vibrations, tube supports are installed. However, due to manufacturing considerations, clearance always exists between tubes and supports. This in turn can lead to tube damage due to fatigue and/or wear at the support locations. This work presents an experimental investigation of the effect of the cross flow on the dynamics of tubes with loose supports. Single flexible parallel triangle array with a pitch-to-diameter ratio of 1.5 subjected to single phase cross flow was considered. Details of the effects of support clearance on the fluidelastic threshold and impact force are discussed. Tube response and tube/support interaction parameters are presented.