月池对钻井船阻力性能的影响研究

  目的  月池是一种从甲板至船底的贯穿船体的开口结构。船舶航行时，月池内流体的复杂流动会给阻力性能带来严重影响。  方法  采用计算流体动力学（CFD）方法对带月池船舶的静水阻力及月池流场进行数值模拟，并对阶梯型与切角型这2种典型月池改进型式的阻力性能进行验证。  结果  结果显示，月池的设置使得船舶总阻力增幅达50.88%，产生的月池阻力与压差阻力的大幅增加值接近，阶梯型和切角型月池对月池增阻的最大降低幅度分别可达80%和40%。流动细节详细呈现了流场内的漩涡运动过程、月池引起阻力增加的规律以及改进型式月池对月池增阻的改善机理。  结论  月池引起的阻力变化与流场内的周期性漩涡运动密切相关，并随航速变化有所差异。阶梯型月池增加了流体运动的阻尼，切角型月池缓解了漩涡对后池壁的强烈作用，能够较好地降低月池引起的增阻。

Research on influence of moon pool on resistance performance of drillship

  Objectives  The moonpool is a type of opening structure through the hull from deck to bottom, but it often brings adverse impacts on the performance of resistance due to its complex flow.  Methods  The computational fluid dynamics(CFD) method was utilized to perform numerical simulations of resistance and flow field of a ship with moonpool in still water. Meanwhile, the resistance performance of two typical modified moonpools, recess type and corner-cutting type, was verified and the improvement mechanism of resistance increase was studied.  Results  The total resistance of the ship increases by 51% with the setting of moonpool, and the moonpool resistance is close to the great increment of pressure resistance. The maximum reductions of added moonpool resistance can separately reach 80% and 40% by the recess type and corner-cutting type moonpools. And the flow details show the process of vortex motions in the flow field, the law of resistance increase caused by moonpool and the improvement mechanism of added moonpool resistance by the modified moonpools.  Conclusions  The resistance variation is closely related to the periodic vortex motions in the flow field, which differs in different speeds. Moreover, the recess type moonpool increases the damping of fluid motions and the corner-cutting type moonpool alleviates the strong effect of the vortex on the back wall of moonpool, therefore the modified types are able to reduce the increased resistance induced by moonpool.