DEVELOPMENT OF PREDICTION METHOD FOR BEHAVIOR OF TOTAL SYSTEM INCLUDING FLOATING BODY-RISER-MOORING LINE INTERACTION

为了研究带有柔性立管的系泊浮体在波浪、风、流等自然环境条件下的行为，需要考虑浮体、系泊缆和立管之间的相互作用。这种相互作用表现为非线性，即在波浪、风、流均为高斯分布的情况下，浮体运动、立管内力和系泊缆张力的响应均为非高斯分布。因此，为了预测上述响应的极值，我们必须在时域内开发计算机程序，并通过相应的实验进行验证。在时域内，考虑了柔性立管与系泊浮体的相互作用，编制了柔性立管系泊浮体非线性动力学计算程序本文首先介绍了立管动力学的基本理论和方法，然后介绍了立管动力学的基本理论和方法，并在此基础上建立了立管动力学的计算程序，最后针对上述程序的验证，开发了立管三维特性的光学测量装置。研究了柔性立管底端行为的混沌现象特征，建立了考虑浮体与立管相互作用和只考虑Keulegan carpenter数变化的立管段阻力的浮体与立管动力学实用分析方法。但当同时考虑阻力和升力时，计算结果会出现偏差。这是今后要解决的重要课题。

In order to investigate the behavior of a moored floating body with flexible riser pipes under natural environment conditions such as wave, wind and current, it is necessary to take account of interaction among a floating body, mooring lines and riser pipes. This interaction reveals nonlinearity which means that responses of motions of afloating body internal forces of riser pipes and tension of mooring lines are all non Gaussian even though wave, wind and current are Gaussian. Therefore in order to predict extreme values of above mentioned responses, we have to develop the computer code in time domain which should be validated by the corresponding experiments.At first , the authors developed the computer code for nonlinear dynamics of moored floating structure with flexible riser pipes in time domain which take into account the interaction between a moored floating body and riser pipes.Secondly they completed the CFD code for hydrodynamics on 2D circular section in separated oscillating flow in time domain.Thirdly they developed the computer code for riser pipe dynamics which is connected with the CFD code.At last, with regard to the validation for the above mentioned computer codes, they developed the optical apparatus for measuring 3D behavior of flexible riser pipes. They wade clear the characteristics of the chaotic phenomena of the behavior of the bottom end of the flexible riser pipes.Finally they established the practical analysis method for dynamics of a floating body and riser pipes which consider interaction effect between a floating body and riser pipes, and also which take account of only the drag force on a riser pipe section in which Keulegan carpenter number varies. However the computation diverges when not only drag force, but also lift force are considered at the some time. This subject is the important one solved in future.