整流罩对深海立管水动力影响的数值模拟研究

CFD Simulation Study on Hydrodynamics Impact of Marine Risers with Fairings

应用CFD大涡模拟方法,对附有整流罩的深海立管的水动力影响效果进行了三维数值模拟。对不同的弦厚比在雷诺数分别为3 900、10 000和20 000条件下进行模拟分析,得到立管后方阻力系数、升力系数、斯特劳哈尔数及其频谱等特性。模拟结果表明:整流罩对立管升力和阻力有明显的抑制效果,相较于光滑立管,阻力系数均值降幅最大达到24.1%,升力系数均方根值降幅最大达到81.1%。阻力系数均值随弦厚比的增加先减小后趋于平稳升力系数均方根值随弦厚比的增加而增加。对比结果显示,弦厚比为1.2~1.6时,整流罩对立管的升力和阻力抑制效果较好。

A study on the effect of fairings on hydrodynamics impact of marine riser is carried out by using the CFD technique through Large Eddy Simulation（LES）. The simulation is analyzed under the condition of different chord thickness ratio according to the Reynolds number at Re=3 900, 10 000 and 20 000. The variations of lift coefficient drag coefficient and frequency analysis of its power spectrum are discussed. The study reveals that the riser with fairings has well performance. The drag coefficient has the largest decline reached 24.1% and the root mean square value of lift coefficient has the largest decline reached 81.1% in comparison with a smooth bare riser. However, with the increase of chord thickness ratio, the drag coefficient of the riser will be increased and then become smooth. The root mean square value of lift coefficient increases with the increase of chord thickness ratio. After comparison, it concludes that the chord thickness ratio is 1.2~1.6 is better.