Dynamics of a vertical riser with weak structural nonlinearity excited by wakes
Dynamics of a vertical riser with weak structural nonlinearity excited by wakes
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DOI：
10.1016/j.jsv.2008.03.023
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发表时间：
2008-08
影响因子：
4.7
通讯作者：
M. Keber;M. Wiercigroch
中科院分区：
文献类型：
--
作者：
M. Keber;M. Wiercigroch
本文研究了弱结构非线性对海洋立管涡激振动（VIV）动力特性的影响。立管动力学与周围流体流动的耦合是通过将尾流振荡器附加到结构的简化模型来实现的，该简化模型是通过应用不变流形技术来推导非线性简正模式而获得的。通过比较线性和非线性结构的自由响应，发现结构非线性对立管的振动具有刚化效应，当将内部流动纳入模型时，这种刚化效应变得更加明显。因此，在耦合系统中，响应对于结构以及对于流体变量被显著地修改。
In this paper we investigate the effect of a weak structural nonlinearity on the dynamical behaviour of a vertical offshore riser subjected to vortex-induced vibration (VIV). Coupling of the riser dynamics with the flow of the surrounding fluid is achieved by attaching a wake oscillator to a reduced model of the structure, which is obtained through the application of the invariant manifold technique for the derivation of nonlinear normal modes. By comparing the free responses of the linear and the nonlinear structure, it was found that the structural nonlinearity has a stiffening effect on the oscillation of the riser, which becomes more pronounced when the internal flow is incorporated into the model. Consequently, in the coupled system, the response is considerably modified for the structure as well as for the fluid variable.