基于CFD技术的OC5漂浮式风机横摇阻尼

Roll Damping of OC5 Floating Offshore Wind Turbines Based on CFD Simulation

漂浮式风机受风载影响,在浪流中阻尼特性不同于常规海工结构物。以OC5项目漂浮式风机基础为对象开展了其横摇阻尼特性研究,采用RANS法、SST k-ω湍流模型和重叠网格技术,模拟了平台在静水、海流和波浪条件下的横摇自由衰减运动,并计算分析了其线性和非线性阻尼系数大小。结果表明,采用该方法得到的结果与水池试验结果基本吻合,平台横摇角度小于10°时,平台的非线性阻尼较小,线性阻尼假设的理论解可以较准确地描述平台的横摇运动;通过浪流干扰过滤发现,海流和波浪会明显增大横摇阻尼,与静水相比,衰减系数增大约1.5倍。因此,做漂浮式风机基础耐波性设计时,浪流对横摇阻尼的影响不可忽略。

The damping characteristics in wave and current of floating offshore wind turbines is different from the conventional offshore structures because of wind loads.The study on the roll damping charicteristics of floating offshore wind turbines foundation based on OC5 by RANS,SST k-ωand turbulence model method is developed.The free decay motion of the platform under the conditions of still water,ocean current and wave is simulated,and the damping coefficients of linear and nonlinear are calculated and analyzed.It is found that when the roll angle of the platform is less than 10°,the nonlinear damping of the platform is small,and the theoretical solution of the linear damping hypothesis can accurately describe the roll motion of the platform.It can be found from wave and current interference filtering,the ocean current and wave would increase the roll damping,the attenuation coefficient increases by nearly 1.5 times as much as the static water free attenuation.Therefore,when the potential flow method is used to calculate the input critical damping of hydrodynamic force,the influence of wave and current can not be neglected.