Stability and Upsetting of Small High-Speed Boat

对某小型高速船的稳定性和倾覆进行了研究，得到的主要结果如下：(1)在风洞中研究了该艇的气动特性。有时，当艇从水面跃起时，空气动力升力引起的扰流力矩会变得非常大。(2)测量了不同工况下作用在船体上的水动力和力矩。从实验中发现，船在静水中基本稳定。(3)用透明塑料模型观察了船底和湿表面的流动现象，发现表面张力对小模型的流动现象有重要影响。(4)通过建立运动方程，尝试对机动运动进行仿真研究。此仿真可用于解决特定问题。(5)倾覆的过程有：(1)自由水面上的扰动使艇开始起跳；(2)在起跳过程中，艇的纵倾和后跟发生变化，艇体保留了较大的气动升力和力矩；(3)离开水面时，没有稳定的水动力，艇开始起跳。

The stability and the upsetting of a small high-speed boat were investigated, and the main results obtained are as follows;(1) The aerodynamic characteristics of the boat were studied in a wind tunnel. Sometimes, the upsetting moment caused by aerodynamic lift becomes very large if the boat jumps from the water surface.(2) The hydrodynamic forces and moment acting on the boat hull were measured in the various running conditions. From the experiments, it was found the boat is generally stable in the still water.(3) The flow phenomena in the boat bottom and the wetted surface area were observed with a transparent plastic model and it was found, the surface tension gives the important effects on the flow phenomena of small model.(4) A simulation study of maneuvering motion is attempted by formulating the equations of motion. This simulation available to solve specific problems.(5) The process of upsetting are, (i) the boat begins to jump caused by some disturbances on the free surface, (ii) during the jumping, the boat changes its trim and heel and the hull reseives comparatively large aerodynamic lift and moment, (iii) leaving the water surface, there is no stabilizing hydrodynamic force, then the boat goes to upset.