半潜式钻井服务支持平台随机风载荷特性研究

风载荷是海洋平台设计载荷之一,直接关系到平台稳性,确定平台在不同工况下的风荷载对于平台安全设计具有重要的工程意义.该文基于Fluent软件结合自编UDF程序,考虑Davenport、NPD以及API三种典型风谱的影响,利用简谐波叠加法将风谱由频域转换为时域内的随机脉动风速,引入雷诺平均法求解NS方程结合分离涡(DES)湍流模型对半潜式钻井服务支持平台在自存海况下的风力和风倾力矩开展了数值研究,并将数值模拟得到的最大风力及风倾力矩与ABS、DNV以及CCS的计算结果进行了对比验证.计算结果表明:平台受到的风力和风倾力矩与风谱自身特性、平台倾斜角及风向角等因素密不可分;同一工况下采用Davenport与NPD风谱计算时平台受到的平均风力(矩)较为接近;NPD风谱作用时平台受到的随机最大风力(矩)最大;采用API与NPD风谱计算时,各工况下最小风力(矩)随风向角的变化趋势、计算结果均基本一致.

Characteristic Study of the Random Wind Load on Semi-submersible Tender Support Platform

Wind load is one of the most important loads acting on offshore platform, and it is direct-ly related to the stability of platform. So it is necessary to determine wind load on various conditions in the design of platform. By using software Fluent and self-compiled program UDF, the wind force (moment) of the semi-submersible support platform in survival condition is numerically calculated. And, the numerical simulation is based on the Reynold's average NS equation and DES numerical model. Then, typical spectrum Davenport, NPD and API in frequency-domain were converted into random fluctuating wind in time-domain by the superposition of simple harmonic waves. The maxi-mum wind forces/moments are compared and verified with results defined by CCS, DNV and ABS rules. As is concluded from the study: wind forces (moments) of the platform are related to wind spectrum characteristics, wind directions and the tilt angle of platform. On the simulation of three wind spectrums, the maximum wind force (moment) of NPD spectrum is biggest. Mean wind forces (moments) of Davenport and NPD spectrum are close. The minimum wind forces (moments) of Dav-enport and NPD spectrum change in almost same trend corresponding to different wind directions.