作业水深对半潜平台气隙影响的比较研究

结合水池试验结果,对数值模拟粘滞曳力和辐射阻尼进行了修正。考虑平台所受的风、浪、流载荷以及全尺寸锚泊系统对平台运动的影响,基于锚泊和ATA定位方式,选取四种典型计算工况,对平台在不同作业水深下气隙和波浪砰击进行研究。研究结果表明:平台在同等工况下,工作水深对两种定位方式下平台运动响应能量谱、关注点气隙响应能量谱影响敏感。关注点处负气隙以及波浪砰击次数随着工作水深的增加而加剧。ATA定位平台较之于锚泊定位平台的随动性更好,可有效减小平台与水质点相对运动。工作水深引起ATA定位下平台关注点的砰击次数、气隙变化以及改善幅值优于锚泊定位。在平台设计过程中应该重视工作水深对平台气隙和波浪砰击的影响。

A comparative study of the influence of different operating water depths on air gap of semi-submersible platforms

Based on the results of the towing experiment, the viscous drag and radiation damping of nu-merical model were amended, considering wind load, wave load, current load, the influence of full size mooring system on the motion of platform, four typical conditions are selected based on mooring and ATA positioning mode.Also the influence on air gap and wave slamming with different operating water depths is analyzed. And a sensitivity study is made, which shows under the same operating conditions, platform mo-tion response energy spectrum and air gap response spectrum of the measurement point have great re-sponse to the water depths with two positioning modes. As operating water depth at the measurement point increases,so does the negative air gap and the number of wave slamming.Compared with the mooring plat-form,the ATA positioning platform has better follow-up performance which can effectively reduce the rel-ative motion between the platform and the water particles. Under the ATA (Automatic Thruster Assistance) positioning,the number of wave slamming, the change of air gap and the improved amplitude caused by op-erating water depth at the measurement point are better than under the mooring positioning.The conclusion shows that the more attention should be focused on the influence of operating water depth on platform air gap and wave slamming.