考虑阻尼比的Spar式浮式风力机基础结构涡激运动特性研究

STUDY ON VORTEX INDUCED MOTION CHARACTERISTICS OF SPAR-TYPE FLOATING BASE STRUCTURE FOR OFFSHORE WIND TURBINE UNDER DIFFERENT DAMPING RATIO

利用数值模拟方法对不同阻尼比条件下Spar式浮式风力机基础结构进行涡激运动特性的研究。从涡激运动响应幅值、频率比、位移、升力及拖曳力等方面研究Spar式浮式风力基础结构涡激运动的关键特性。研究表明:涡激运动上端分支对应的频率比为f_(y)/f_(n)≈1,且该分支出现最大幅值。随着阻尼比的增大,上端分支约化速度范围有减小趋势。低阻尼比下,力与位移的曲线出现"拍"现象;下端分支对应的频率比f_(y)/f_(n)均大于1,不随阻尼的改变而发生变化。上端分支与下端分支间,存在一过渡区域,该区域对应的斯托哈尔数St≈0.17,不随阻尼比的改变而改变。

The vortex-induced motion characteristics of Spar-type floating base structure for offshore wind turbine with different damping ratios are studied by numerical simulation.The study for the key characteristics of vortex-induced motion of Spar-type floating base structure for offshore wind turbine commences with vortex induced motion response amplitude,frequency ratio,displacement,lift force and drag force etc.The results showed that the maximum peak value is appeared on the upper branch with the frequency ratio is about 1.With the increase of damping ratio,the reduced velocity range of upper branch tends to decrease.The"beat"phenomenon of force and displacement curve appears at low damping ratio.The frequency ratios of lower branch are greater than 1 and does not vary with damping.A transition region existing between the upper branch and the lower branch,the corresponding strouhal number is about 0.17 and it does not change with the change of damping ratio also.