Conventionally,the aligned wind and waves is considered the worst load case in designing an offshore wind turbine. However, the dynamic characteristics of floating offshore wind turbines (FOWT) differ from fixed wind turbines and the effects of the wind-wave loads on the FOWTs still require further investigation. In order to study the effects of misaligned wind and waves on the performance of mooring system of the FOWTs, FOWT models were adopted and the time domain simulations using the FAST-Orcaflex software were conducted accounting for variable wind-wave intersection angles. In the study, multiple sea states and different operational conditions were considered and results of tensions in selected mooring line and the platform motion responses were obtained from the simulation. Furthermore, detailed analysis of the results were performed. It is revealed that under aligned wind and waves,the largest tension in mooring line occur,along with the greatest platform motions(in five degrees of freedom except yaw). However,the misaligned wind and waves may cause greater fatigue damage in the mooring line in the moderate sea states when the wind turbine is parked. Therefore, it is suggested that two wind-wave intersection angles should be accounted for, i.e. 0° and 90°, when assessing the fatigue damage of the mooring lines under moderate sea states. For the long-term fatigue analysis of the mooring lines, misaligned wind and waves should be considered with reference to the wind and wave direction distribution scatter diagram.%海上风机结构的设计中通常只考虑共线风浪.然而浮式风机的动力特性与传统的固定式风机有显著不同,风浪荷载对其结构的影响仍需进行深入研究.为探究风浪夹角变化对浮式风机系泊的影响,采用FAST-Orcaflex软件建立了浮式风机的耦合模型并进行了时域分析,得到了多种代表海况及不同风机运转状态下系泊的张力和平台的运动响应,并对模拟结果进行了分析.结果表明:共线风浪会造成最大的系泊张力以及除艏摇外最大的平台运动响应;但在温和海况下,风机停机时,不共线风浪会造成更大的系泊疲劳损伤.因此建议:在评估温和海况下系泊的疲劳损伤时,至少考虑风机停机状态下风浪夹角为0°和90°的工况;在系泊的疲劳寿命评估中,应结合风浪作用方向散布图,考虑温和海况下的风浪不共线工况.
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