Study on motions of a sailing boat

关于帆船的研究工作已经有很长的历史了，但它们只是基于优秀水手和设计师的经验的经验。其中一个例外是针对美洲杯的研究。即使是这项研究也只是关于稳定的航行表现。这项研究是关于非定常性能，如追尾和俯仰，这是帆船比赛和远洋巡航的关键。研究结果如下：1.建立了考虑水动力作用于横倾不对称船体的四自由度运动数学模型。2.利用实海试验船的运动记录，建立了数学模型中主要非定常水动力系数的识别方法。3.研制了实海试验船运动测量系统，并进行了高精度的测量。4.为进行无线电操纵帆船模型的自由航行试验，对水池风向进行了重新布置。测量了船在入射海浪作用下的减速。对减速机理进行了研究。5.在风洞中进行了风帆的强制俯仰试验。测量了FRP夹层结构的附加质量、阻尼系数和升力折减，并与基于二维振动翼理论的条带理论进行了比较，进而对FRP夹层结构进行了有限元分析，以得到轻质、刚性和坚固的船体。为了验证理论的适用性以及获得实际的生产技术诀窍，进行了部分结构设计。

Research works on sailing boats have a long history, but they are only empirical based on experiences of good sailors and designers. One of the exception is research for America's cup. Even that research is just on steady sailing performance. This research is on unsteady performance such as tacking and pitching, which are crucial for yacht races and ocean cruise. The following results are obtained.1.We developed the tacking simulator based on a mathematical model of four degrees of freedom of motion considering hydrodynamic forces acting on the heeled asymmetrical hull.2.We developed the identification method of the main unsteady hydrodynamic force coefficients of the mathematical model utilizing the recorded motion of the boat tested in real sea.3.We developed the measuring system of the boat motion tested in real sea, and measured it in good accuracy.4.The direction of the wind fun of the basin with wave, wind and current was rearranged in order to carry out free running tests of a radio controled sailing boat model. Speed reduction of the boat due to incident waves was measured. The mechanism of the speed reduction was investigated.5.Forced pitching tests of the sail were carried out in the wind tunnel. Added masses, damping coefficients and lift reduction were measured, and compared with newly developed strip theory based on 2-D oscillating wing theory.Furthermore FRP sandwich structures were analyzed by FEM in order to obtain light, rigid and strong hulls. Partial structures were made to confirm the applicability of the theory as well as to obtain practical production know-how.