The semisubmersible platform is one of the most important equipment for the exploitation of deep-sea oil and gas. And its survival and operational capacities depend on the towing and motion performances. The present work investigates the properties of different platform component designs based on their towing and motion performances under wind and waves by using an integrated computational fluid dynamics (CFD) method. The joint application of RANS and a VOF/6-DOF solver compiled in a new Fluent UDF Library is adopted for the main calculation. Numerical simulations and results demonstrate that the VOF/6-DOF solver is accurate and stable, which could achieve the same functions as the previous OpenFOAM scheme. In order to acquire a better towing performance, different shapes are suggested for the pontoon end shape, the column cross section, and the brace longitudinal section, respectively. As to the motion response, among all the three design selections, the column cross section has the greatest influence on the whole platform. The simulation results reveal that circle section increases the roll and pitch response and reduces the heave response, to which the square section is adverse.

中文翻译：

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基于CFD / 6-DOF方法的半潜式平台在风浪作用下的性能评估

半潜式平台是深海石油和天然气开采的最重要设备之一。其生存能力和操作能力取决于牵引和运动性能。本工作通过使用集成的计算流体动力学（CFD）方法，基于不同平台组件设计在风和波浪下的牵引和运动性能，研究其性能。主要计算采用RANS和在新的Fluent UDF库中编译的VOF / 6-DOF求解器的联合应用程序。数值模拟和结果表明，VOF / 6-DOF求解器是准确且稳定的，可以实现与以前的OpenFOAM方案相同的功能。为了获得更好的牵引性能，建议对浮桥端部形状，柱子横截面，和支架纵向截面。对于运动响应，在所有三个设计选择中，柱截面对整个平台的影响最大。仿真结果表明，圆形截面增加了滚动和俯仰响应，并减小了升沉响应，而方形截面则不利。