Prediction of the Seakeeping of High speed Ships

本研究的目的是开发一种方法来预测和评估的耐波性的高速船舶，如SES，小水线面双体船和水翼船的角度，克服他们的脆弱性，以波涛汹涌的大海。结果表明：1. (1)本文提出了一种计算双体船体型高速船在高弗劳德数波浪中的水动力和波浪激振力的新理论。该理论正确地解释了高速对水动力的影响，尽管与其他复杂的技术相比，计算量很小。这是直接与这个理论，把附着在主船体的水翼的影响到水动力。(2)水池模型试验验证了理论的正确性。首先，我们发现由本理论预测的垂荡和纵摇的附加质量和阻尼系数与强迫运动试验得到的结果有很好的相关性。本文采用自行研制的实验技术，对高速双体船辐射和绕射产生的波浪特性进行了测量和分析。这些特性与高速船在波浪中的附加阻力密切相关。并证实了它们与理论值的相关性。(3)本文提出了一种理论来预测作用在高速行驶的水翼上的水动力。这可以很容易地与（1）和（2）中描述的理论结合起来。2.编制了一个计算程序，可以计算双体船在斜波和短峰波中的运动和波浪力。该程序是设计在海道中具有更好性能的高速船舶的有用工具。

Objective of this research is to develop a methodology to predict and evaluate seakeeping of high speed ships such as SES,SWATH and hydrofoil boats in the perspective of overcoming their vulnerability to the rough seas. The results are:1. (1) We developed a new theory to predict hydrodynamic forces and wave exciting forces on high speed ships of catamaran hull form in waves at high Froude number. This theory accounts correctly the high speed effects on the hydrodynamic forces despite light computational loads compared with other sophisticated techniques. It is straightforward with this theory to incorporate the effect of hydrofoils attached to the main hull into hydrodynamic forces. (2) Validity of the theory was confirmed by model tests in the water tank. First we found that the added mass and damping coefficients of heave and pitch predicted by the present theory are in good corelation with those obtained by forced motion test. Characteristics of waves produced by the radiation and the diffraction of high speed catamaran were measured and analyzed by new experimental technique we developed. Those characteristics are closely related to added resistance of high speed ships in waves. They were confirmed to be correlated to the theoretical. (3) We developed a theory to predict the hydrodynamic forces acting on a hydrofoil running at high speed under waves with shallow depth of submergence. This can be easily combined with the theory described in (1) and (2). 2.We completed a computer program by which we can compute and evaluate the motions and wave forces of a catamaran running in oblique or short crested waves at very fast speed. This program is a useful tool to design high speed ships with better performances in a seaway.