三类边界条件下隔水套管涡激非线性振动的比较分析

Comparative analysis of vortex induced nonlinear vibration of marine risers under three different boundary conditions

考虑流及波流联合作用,研究了套管的涡激非线性振动.将套管简化为梁模型,考虑3类不同的边界条件,计及莫里森非线性流体动力和涡激荷载,建立套管的涡激振动方程.应用克雷洛夫函数求解套管的固有频率和模态,采用了计算涡激非线性动力响应的迦辽金方法.以东海勘探3号钻井隔水套管为例,研究了不同边界条件下流引起的主共振和波流联合引起的组合共振.计算结果表明:流对套管的动力响应占主导地位,而波的影响不大.分析了3类不同边界条件下隔水套管的涡激非线性动力响应,揭示了波流联合激励下套管复杂的动力响应特性.

Based on the loads of current and combined wave-current, vortex-induced nonlinear vibration of marine rises in deep water was studied. The vortex-induced vibration equation of marine rises was set up with considering the beam mode and Morison＇s nonlinear fluid damp as well as the vortex-excited loads under three different boundary conditions. The Galerkin method was adopted to calculate the vortex induced nonlinear vibration. The response, which included primary resonance induced by current and the composite resonance under combined wave-current for the marine drilling risers of the Donghai 3# were studied. The numerical results show that the dynamic response of marine risers is mainly induced by the current, and the influence of wave may be neglected. Under three different boundary conditions, the vortex-induced nonlinear vibration of marine rises gives the complex response behaviors of marine risers under combined wave-current.