将月牙扰流器按"八"字布置于立管表面用以抑制立管涡激振动,为研究其抑振效果,分析其抑振敏感性,在大型波、浪、流水槽进行涡激振动抑振试验。试验中采用有机玻璃管模拟立管,立管模型长1.5m,外径18mm,壁厚2mm,两端铰接,外流速分别为0.6、0.7m/s。按照不同螺高、螺距及迎水面形式设计8根具有正八字、倒八字抑振装置的不同类型抑振管,同时设计一根与抑振管相同配重的裸管,在立管表面粘贴应变计以测得动态应变数据,经过数据处理得到立管振动位移值。通过各抑振管间以及抑振管与配重裸管之间横向振动位移幅值的对比,研究抑振装置的抑振敏感性。结果表明:在适当尺寸及布置形式条件下,表面按"八"字布置月牙扰流器能够有效抑制立管横向涡激振动;迎水面月牙布置形式不同,抑振效果略显不同,迎水面布置为倒八字其抑振效果优于正八字,但该种抑振装置仍可实现全向性;抑振装置的螺高、螺距对抑振效果有一定影响,螺高增大、螺距减小有利于提高抑振效果。

We presented experimental investigation concerning vortex induced vibration(VIV) of marine risers with crescent spoilers pasted on the surface as the suppression devices and analyses the sensibility in this paper.Several plexiglass pipes with external diameters of 18 mm,wall thickness 2 mm and a total length of 1.5 m are used to simulate marine risers.Risers are able to vibrate in both in-line(I-L) and cross-flow(C-F) direction through universal joints,the current velocity is varied from 0.6 m/s and 0.7 m/s.According to the differences of screw height,screw pitch and erected 八' or inverted,we designed 8 suppression risers and a bare model without suppression devices but with equal load via injecting water.Dynamic strain records were obtained through the dynamic strain gauges which were stick on the surface of the risers.The experimental data are contrastive studied and the results indicate that the suppression devices of crescent spoilers can effectively decrease the displacement of VIV in C-F direction.If the crescent spoiler are pasted in the style of inverted 八',the efficiency is a little better,which doesn't deny the all-direction efficiency.The characters of suppression devices including screw height and screw pitch can influence the efficiency,and the height is higher or the pitch is farther,the efficiency is better.