螺旋侧板截面形状对Spar平台涡激运动的影响研究

处于深水中的Spar平台两侧不断产生周期性漩涡脱落,极易诱发涡激运动,缩短平台疲劳寿命。为探究不同截面形状螺旋侧板对漂浮式风力机Spar平台涡激运动的影响,采用大涡模拟(LES)方法,对亚临界雷诺数流动状态下附加不同截面形状螺旋侧板的平台进行研究,并与光滑平台进行对比,分析其水动力系数及尾涡发放特点。研究表明:螺旋侧板在有效抑制平台升力系数的同时,还会增加阻力系数,圆形截面侧板对平台升力系数的降幅最大,阻力系数增幅最小;螺旋侧板的存在使漩涡脱落频率整体减小,从单一主频发放变为主频和次频发放;圆形截面侧板的漩涡脱落点距离平台最远,发放最为迟缓;在研究范围内,发现圆形截面侧板抑涡效果最佳。

Study on the influence of section shape of helical strakes on the vortex-induced motions of Spar platform

Spar platforms in deep water on both sides suffer from a constant periodic vortex shedding, which will easily induce vortex-induced vibration and reduce the fatigue life. In order to study the influence of section shape of helical strakes on the vortex-induced motions of Spar platform, numerical analysis is carried out for the bare cylinder and Spar platform with different section shapes at Reynolds number Re=3900 by large eddy simulation (LES), including hydrodynamic coefficient and wake flow field. Research shows that the helical strakes are effective in reducing lift coefficient, but will increase drag coefficient, and the circle section strakes are the most efficient which reduced lift coefficient by 94% and increase drag coefficient by 15%. The helical strakes reduce the overall frequency of the vortex shedding and the single frequency is replaced by major and minor frequencies. The circle section has the longest distance before the vortex shedding and has the lowest frequency; and the circle section has the best suppression effect within the range of the research.