Study on Unstable Phenomena in Transverse Stability for High Speed Craft

点击翻译按钮获取中文摘要

It is well known that the transverse stability of a high speed craft might occur the unstable phenomena at running more than a certain speed even though the stability possess adequate static stability at rest condition. The phenomena of this kind are complex, and it will be difficult to investigate the mechanism of the phenomena.This paper is to clear the mechanism of unstable phenomena of transverse stability in high speed craft. The numerical calculations for the dynamic pressure acting on ship's body were carried out on a model craft with ship's length 3.6m by using slender body theory of Maruo.According to the results of numerical calculation, the heeling moment of the craft increased with ship speed increasing, specially with over Froud's number 0.8. This tendency on phenomena was verified by the model test.From these investigations, one of the main reason for unstable phenomena in transverse stability is that the dynamic pressure acting on ship's body changes with ship speed increasing. Simultaneously the distribution of the dynamic pressure will change along to the longitudinal direction, then this pressure causes yaw moment.