波浪作用下钻井船的共振数值计算及分析

Numerical calculation and analysis of resonance of drillship in waves

[目的]带月池的海上平台作业效率及作业安全性要求不断提高,波浪作用下平台自身运动及月池内流体运动带来的共振问题愈发凸显。[方法]为此,基于势流理论的常数边界元法,开发波流与三维物体相互作用的数值模拟计算程序。选取某带月池钻井船,对其运动展开频域数值计算,对无航速时数值模型计算程序的计算结果与水动力软件AQWA计算结果进行对比,验证无航速时所开发计算程序的可靠性。将波流工况计算结果与实验结果对比,验证该数值方法的准确性。[结果]通过比较多种月池长宽比、月池吃水、波浪入射角度以及有、无航速情况下的船舶运动,发现带月池钻井船在升沉和摇摆运动上都会发生共振现象,引入迎流流速会调制和加剧月池的共振。[结论]研究结果可为带月池船舶的运动响应预报及共振抑制提供参考依据。

[Objectives]With the sustained demand for improving operational efficiency and safety of the offshore platforms with moonpools,the resonance problems become more critical due to the motion of platforms in waves and fluid flow in the moonpools.[Methods]To effectively solve this problem based on the constant boundary element method of potential flow theory,this paper developed a numerical simulation program to calculate the interaction between wave currents and three-dimensional objects.By selecting an drillship,we carried out frequency-domain numerical calculations for its motion,compared the calculation results of those of AQWA,verified the reliability of the program,then compared the calculation results of wave and current conditions with those of the experiment,and verified the accuracy of the numerical method.[Results]By comparing the resonance phenomena of ships containing the moonpool in the heave and sway motion under varying length-width ratio conditions and different drafts of the moonpool,different wave incidence angles and with or without sailing speed,the introduction of velocity in the upstream situation will modulate and intensify the common vibration of the moonpool.[Conclusions]The research can provide a reference for predicting the ship's motion response with the moonpool and reduce the risk of resonance.