WEAK AND STRONG-INTERACTIONS IN VORTEX-INDUCED RESONANT VIBRATIONS OFCYLINDRICAL STRUCTURES

Vortex-induced resonant vibrations of cylindrical structures with weak and strong fluid-structure interactions are studied by using the meth od of multiple scales. For weak fluid-structure interaction, the first order approximation only predicts the existence of the main inner res onance. For strong fluid-structure interaction, it generates more inne r resonance phenomena. When the structural elasticity is non-linear th ere may exist subharmonic, superharmonic and main inner resonances. Ho wever, when the structural elasticity is linear there may exist superh armonic and main inner resonances? but no subharmonic resonance may oc cur. The analytical results are verified by numerical integration solu tions. For the case of weak interaction, they are also in good agreeme nt with the known theoretical and experimental results. It is also fou nd that the method of multiple scales, up to the order of approximatio n considered, is not applicable to the study of main inner resonances for strong fluid-structure interaction. (C) 1996 Academic Press Limite d