AN IMPROVEMENT TO THE QUASI-STEADY MODEL WITH APPLICATION TO CROSS-FLOW-INDUCED VIBRATION OF TUBE ARRAYS

A generalization of the quasi-steady theory is proposed, the aim of wh ich is to model the most important unsteady effects neglected by the c onventional quasi-steady assumption Although this generalized model re ferred to as the quasi-unsteady model, can be applied in a vast range of flow-induced vibration problems, including classical aeroelasticity , it was primarily developed to improve the theoretical prediction of the fluidelastic behaviour of a single flexible cylinder positioned in the midst of an array of rigid cylinders. In this context, it is show n that the previous improvement to the quasi-steady theory proposed by Price & Paidoussis can be considered as a particular case of the quas i-unsteady model. Results obtained with the quasi-unsteady model are c ompared to experimental data and to solutions from the Price & Paidous sis model; both modal parameter variation with flow velocity and stabi lity diagrams are considered. This comparison shows that the quasi-uns teady model is a clear improvement on Price & Paidoussis' approach, le ading to a more reasonable agreement with experimental results and pro viding refined insights into the physical mechanisms responsible for f luidelastic instability.