深海系泊浮体物面非线性时域耦合动力分析

摘要

Based on the three-dimensional time domain potential flow theory and the slender rod theory,the body nonlinear time domain coupled dynamic analysis method of a mooring floating body is investigated and proposed.The transient free surface Green function method was extended and applied to simulate the transient position hydrodynamic calculation of a mooring offshore structure in waves.The finite element model is employed to solve dynamic responses of mooring lines.Then asynchronous coupled method is adopted to achieve the coupled dynamic analysis of a floating body and mooring lines,which satisfies the hydrodynamic coupling calculation of a mooring floating body in time domain,and the dynamic coupling between a floating body and mooring lines.The time domain coupled responses analysis program is applied for a mooring semi-submersible platform in the second order nonlinear irregular waves.Both body nonlinear time domain static coupling responses and dynamic coupling responses numerical simulation results,including motion responses of platform and tension responses of mooring lines,are presented and compared with the traditional indirect time domain dynamic coupling responses approach in different random sea conditions.The results show that the dynamic coupling effects are significant and the transient position hydrodynamic calculation of platform has a great influence on the low frequency motion especially on heave motion.So it is necessary to coupled dynamic analysis of a mooring floating body with transient position hydrodynamic calculation in deep sea.%文章基于三维时域势流理论和弹性细长杆理论,研究并提出了深海系泊浮体物面非线性时域耦合动力分析方法.该方法采用时域物面非线性理论方法在瞬态位置直接时域模拟系泊浮体所需水动力,结合有限元方法计算系泊缆索的动力响应,利用异步耦合方法实现浮体和系泊缆索的时域耦合动力求解.既满足系泊浮体时域水动力耦合,又满足系泊浮体和系泊缆索动力耦合.通过对二阶非线性不规则波作用下深海系泊半潜式平台的时域耦合响应特性进行研究,将不同海况下物面非线性时域耦合静力响应和动力响应与间接时域耦合动力响应的三种方法计算结果进行比较.研究结果表明,系泊缆索动力响应明显,平台瞬态空间位置对垂荡低频运动影响较大,有必要在平台瞬时湿表面采用动力响应方法进行深海系泊浮体时域耦合响应分析.