桶形基础平台沉放过程数值模拟分析

Numerical Simulation Analysis of Bucket Foundations Platform Submergence

平台在沉放过程中 ,受到复杂的一阶和二阶流体动力作用 ,为了深入了解沉放过程中平台的运动特性 ,首先建立了桶形基础平台沉放数值模型 ,然后通过格林函数法和平台湿表压力积分来计算一阶和二阶流体动力 ,并耦合求解平台和锚泊线运动方程 ,得到平台的运动响应 .为了验证数值模拟计算的准确度 ,在上海交通大学海洋工程国家重点试验室进行了平台沉放模型试验 ,试验结果与数值模拟符合良好 .数值模拟分析表明 ,平台在沉放过程中主要的运动为纵荡、横荡、纵摇和横摇 ,并且与来波方向有密切关系 ;二阶波浪力对纵荡和横荡有明显的作用 ;整个沉放过程中平台运动比较稳定 。

Bucket foundations platform is subjected to the complicated first order and second order hydrodynamic force in the stage of submergence. To know the character of the platform motion response, a numerical model of platform was set up, first order and second order hydrodynamic forces were calculated by Green function and pressure integral of the wet surface, and coupling-motion equations of platform and mooring lines were solved. An experiment was made in the State Key Lab. of Ocean Engineering of Shanghai Jiaotong University to verify the simulation. The results of simulation agree well with the results of experiment. It can be drawn from the numerical simulation that the main motion directions are surge, sway, pitch and roll, which relate to the wave heading; the second order wave force has obvious action on surge and sway; the stage of self-ballast submergence is stable and practical.