月池的尺度效应对钻井船航行阻力的影响特征研究

Research on the influence of the moonpool scale effect on the navigation resistance of drilling ships

因雷诺数不同,月池的尺度效应会影响钻井船航行阻力。本文以全月池为研究对象,分别采用雷诺时均方法中的三种湍流模型,模拟月池内流体的强非线性活塞及晃荡运动,分析月池中纵剖面处的流体运动,对比试验结果,确定月池内流体运动的数值模拟方法。以实尺度月池为研究对象,对比模型尺度下月池内的流体运动,分析月池尺度效应的产生原因;通过比较模型试验换算结果,研究月池尺度效应特点及对钻井船航行阻力的影响特征。结果表明,由月池尺度效应带来的阻力占钻井船航行总阻力百分比可达17.1%,且随傅汝德数增加而增大,采用实尺度数值模拟可有效避免月池尺度效应,得到更精确的钻井船阻力。

Due to the different Reynolds number,the sailing resistance of drilling ships can be affected by the scale effect of a moonpool.In this paper,three different turbulence models are used to simulate the strong nonlinear piston and sloshing motion of the fluid in a moonpool.By analyzing the fluid motion in the moon⁃pool and comparing the numerical results with the model test results,the numerical simulation method of flu⁃id motion in the moonpool is determined.The reason of the generation of moonpool scale effect is analyzed by comparing the fluid motion in the moonpool under full scale and model scale respectively.By comparing the converted results of the test resistance with the full scale results,the characteristics of the moonpool scale ef⁃fect and its influence on the navigation resistance of drilling ship are studied.The results show that the resis⁃tance of the moonpool caused by the scale effect amounts to 17.1%of the total resistance and increases with the growth of Froude number.The scale effect of the moonpool can be effectively avoided by adopting fullscale numerical simulation to get a more accurate drilling ship resistance.