U型水舱在船舶中的垂向布置问题

基于“船舶－被动式U型减摇水舱”系统运动微分方程，分析了U型减摇水舱在船舶中的垂向位置对船舶横摇质量惯性矩、横摇复原系数、横摇固有频率、船舶与水舱的耦合惯性矩等系统方程参数及对船舶横摇运动和舱内液体运动的影响。结果表明，水舱垂向位置高船舶横摇中心越远，由舱内液体引起的船舶横摇质量惯性矩和横摇复原系数越大，船舶横摇固有频率则越小。而耦合惯性矩则随水舱布置高度的变化呈减小的趋势。对于各种不同类型的船舶，存在一个使舱内液体不发生振荡的奇异位置，这时水舱不产生任何的减摇效果，船舶的横摇运动与不安装水舱时相同。利用我校所研制的减摇水舱模型性能摇摆台进行了水舱模型不同垂向布置时的强迫振荡试验，试验结果与仿真结果具有很好的一致性。指出了除水舱固有频率和水舱阻尼外，水舱在船舶中的垂直方向位置也是影响水舱减摇性能和船舶减摇后的横摇运动的主要因素之一，在减摇水舱设计初期应当予以考虑。

Research on Vertical Location of U-type Anti-rolling Tank in Ship

In this paper, based on the motion equations of ship and passive U type anti rolling tank system, a detailed analysis is made of the effect of tank vertical location on the parameters of system equations such as the rolling inertia moment, the rolling righting moment coefficient, the ship rolling natural frequency, the coupling inertia moment between the ship and the tank, and on ship rolling motion and the motion of water in the tank. It shows that the farther away the tank vertical location is from the rolling center of the ship, the larger the rolling inertia moment and the rolling righting moment coefficient become, and the less the rolling natural frequency of the ship is. The coupling inertia moment inclines to decrease with the increase of the height of tank location. There is a singular location where the water in the tank does not move back and forth so the anti rolling tank does not bring forth any stabilizing effectiveness for the ship and the rolling motion of the ship is identical with that of an unstabilized ship. The forced oscillation test results on the test rolling analog table developed by the Ship Stabilizing and Control Technology Research Institute, are in good accordance with the simulational ones for different vertical locaton of the tank model. It indicates that in addition to the tank natural frequency and the tank damp, vertical location of the U type anti rolling tank is also one of main factors influencing on the stabilizing effectiveness of the tank, which should be deliberated on during the initial phase of the U type anti rolling tank design.