干涉对海洋立管涡激振动影响实验研究

Experimental investigation of vortex-induced vibration of marine risers with interference

文章进行了干涉对海洋立管涡激振动影响的实验研究,实验分为立管前后排列和并肩排列两部分。立管间距为3-10倍直径,模型材料采用有机玻璃,长1.5 m,外径18 mm,壁厚2 mm,边界条件均为铰接,外流速分别从0.3-0.8 m/s,每级增加0.1 m/s。通过在立管表面粘贴应变计获得动态应变数据,分别从立管的横向动态响应、振幅、频率等方面对前后排列、并肩排列立管以及和单独立管的实验数据进行对比研究。结果表明,当有外流通过时,立管会受到其他立管尾流的影响,漩涡脱落引起的振动由于间距及排列方式的不同而显著不同,使得立管的动力特性、动力响应以及漩涡的脱落形式同单个立管相比均有较大的变化。

This paper presents experimental investigation concerning vortex-induced vibration of marine risers with interference. The arrangements of the risers involve tandem and side-by-side. Centre-to-centre distances from 3 to 10 diameters were studied. Model materials were made of plexiglass, with external di- ameters of 18 ram, wall thickness 2 mm and a total length of 1.5 m. Both risers are able to vibrate in the in-line and cross-flow direction through universal joints, the current velocity was varied from 0.3 m/s to 0.8 m/s, in increments of 0.1 m/s. Dynamic strain records were obtained through the dynamic strain gauges which were stick on the surface of the risers. The experimental data were contrastive studied by dynamic response of cross-flow direction, amplitude and frequency, respectively. The experimental results indicate that when the riser is in the wake of another, the oscillations induced by the vortex shedding are consider- ably modified and strongly depend on the distance of the two cylinders. Compared with the single riser, dy-namic characteristics, dynamic response and the form of vortex shedding are considerably modified.