Flow-induced vibration of an Euler-Bernoulli beam

Flow-induced vibration of a fixed-fixed elastic cylinder with a large aspec t ratio ( approximate to 58) is considered. The structural vibration is mod elled by the Euler-Bernoulli beam theory, and the normal mode method is use d to analyze the structural response. The flow field are resolved using a f inite element method and the flow-induced forces are thereby calculated. Al together two different cases are examined, one at resonance and another at off-resonance. Results thus obtained are compared with experimental measure ments and discrete-parameter model [a two-degree-of-freedom (2-d.o.f.) mode l] analysis. The comparison shows that, while the 2-d.o.f. model gives reas onable prediction of the mid-span vibration displacements for the resonant and off-resonant case, the present method yields the span-wise multi-mode r esponse of the cylinder similar to that observed experimentally. Based on t hese results, a correction formula is derived to estimate the span-wise vib ration from the 2-d.o.f. model result. Correlation results are also present ed to show that fluid-structure interactions mainly affect the phase relati on between the fluid forces and the col:responding vibration of the cylinde r. Such influences have different effects along the cylinder span. (C) 2001 Academic Press.