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本文利用线性分析法研究了半潜式钻井平台在规则波浪作用下的升沉运动,编制了对应的计算机程序,并以“南海二号”钻井平台为例进行计算,给出了计算结果同实验结果的比较曲线。从而指出:(1)影响半潜式平台升沉的波浪激振力包括垂直方向的下船体阻力和惯性力,立柱的惯性力和切向摩擦阻力、变浮力。在远离共振区时,附加惯性力和变浮力占优势,阻力可以忽略不计,平台对规则波的响应趋于线性;在共振区附近时,附加惯性力和变浮力大小接近,方向相反。此时阻力不容忽略。平台升沉振幅与波高之比随波高的增加而减小。此区间平台的升沉与波高不存在线性关系。(2)平台的升沉转换函数随着水深的增加而增大,当水深达到一定值以后,水深的变化对升沉转换函数的影响很小。(3)平台的升沉转换函数随着船向与波浪传播方向间的夹角的增大而减小。
In this paper, the linear analysis method is used to study the heaving motion of semi-submersible drilling rig under the action of regular wave. The corresponding computer program is compiled and the calculation is made with the example of “Nanhai No.2” drilling rig. The results of the comparison curve. It is pointed out that: (1) The wave excitation force that affects the subsidence of the semi-submersible platform includes the vertical hull resistance and inertial force, the column inertial force, tangential friction resistance and variable buoyancy. When away from the resonance zone, the additional inertial force and variable buoyancy are dominant, the resistance is negligible, and the response of the platform to the regular wave tends to be linear. In the vicinity of the resonance zone, the additional inertial force and variable buoyancy are close in the opposite direction. At this point the resistance can not be ignored. The ratio of platform amplitude to wave height decreases with the increase of wave height. There is no linear relationship between heave and wave height of this interval platform. (2) The heave-sink transfer function of the platform increases with the increase of water depth. When the water depth reaches a certain value, the change of water depth has little effect on the heave-sink transfer function. (3) The heave transfer function of the platform decreases with the increase of the angle between the direction of ship and the wave propagation.