Spar型海上浮式风力机系统运动耦合计算方法

Coupled method for predicting motions of Spar-type offshore floating wind turbine systems

针对海上浮式风力机系统(FOWTs)与风浪流相互作用问题,建立了时域非线性耦合动力学方程和流体动力数学模型,采用Fortran语言编程、时域频域转换和龙格-库塔法迭代求解方法,分析定常风、规则波和随机风浪环境下,Spar型FOWTs除艏摇之外的5自由度运动响应特性。结果表明,额定定常风速时,风力机系统5自由度运动响应的平均值和峰峰值都受影响,而其他定常风速不影响纵向运动响应的峰峰值;规则波对5自由度运动响应的平均值影响很小,但峰峰值明显增大;在随机风浪下,FOWTs的纵荡(摇)和升沉运动分别不同程度地出现明显低频性和波频性,而且与风速相关。分析方法及其结果为海上FOWTs的运动性能设计提供参考。

In this study,we established non-linear time-domain coupled dynamic equations and aero / hydro-dynamical models to study the interaction between wind waves and floating offshore turbine systems（ FOWTs）. We used Fortran code,time-frequency domain transformation,and the Runge-Kutta iteration method to solve nonlinear equations. We analyzed the 5DOF motion response characteristics of Spar FOWTs,except yawing,under steady wind wave,regular wave,and random wind-wave conditions. The results show that constant wind affects the average and peak-to-peak values of surge,pitch,heave,sway,and roll at the rated wind speeds,while it does not affect the peak-to-peak values of sway at other wind speeds. In addition,regular waves have only marginal effect on the average values of surge,pitch,heave,sway,and roll,but enlarge their peak-to-peak values. Under random wind and wave conditions,we characterized the system＇s sway and pitch motions for low and high wave frequencies,depending on the wind speed. The results of this study provide references for the design and hydrodynamic analysis of offshore floating wind turbine systems.