Approach Flow Direction Effects on the Dynamics of a Loosely Supported Tube Array
A major threat to tube bundle integrity is the flow-induced vibration (FIV). FIV is manifested through several mechanisms including the most severe mechanism; fluidelastic instability (FEI). FEI can be controlled by using tube supports. However, clearance between the tube and support is required to allow for thermal expansion which causes intermittent tube support resulting in fretting wear and tube failure. The aim of this study is to investigate the effect of the approach flow velocity on the dynamics of tubes with loose supports. Experiment set up in a wind tunnel was developed to test single flexible tube (triangle and square) array subjected to cross-flow. The tube bundle was precisely designed to maintain a constant flow resistance for each examined orientation. Effects of flow orientation, support gap on the fluidelastic threshold and tube/support interactions are discussed. The study has shed some light into the complex interaction between tubes and their support.