Study on Estimation of Deck-Wetness for a High-Speed Vessel

我们进行了为期三年（1996 - 1998）的“高速船舶甲板湿度估算研究”。本文的主要结论总结如下：(1)明确了船周定常流动对船舶非定常水动力的影响。我们开发了一种新的方法来预测它们之间的相互作用。研究表明，定常流势的二阶导数项对水动力有重要影响。我们开发了3。将线性朗肯面板法作为预测定常与非定常流动相互作用效应的实用估计方法。与实验结果的对比表明，该方法对预测高速船舶的耐波性是有效的。(3)稳态流动对辐射力的影响较大，对衍射力的影响较小。特别是，它强烈地出现在他们的低频…更多的范围。(4)要准确估计船舶的压力分布，既要考虑自由表面条件，又要考虑船体表面条件的影响。(5)弓部的指关节可以减小弓部衍射波的振幅。因此，它是可取的附加指关节在船头部分，以减少甲板上的湿气。船速度。(6)随着前进速度的增大，定常流动与非定常流动的影响更加显著。特别是船首部分周围的波廓线受船首耀斑形式的强烈影响。因此，为了准确地预测高速船舶的耐波性，有必要开发一种考虑静水面以上船首耀斑影响的新预测方法。(7)研究表明，大多数高速船舶事故与高速船舶的不稳定运动密切相关。因此，迫切需要弄清产生不稳定运动的水动力现象。少

We have performed the Research Project titled "Study on Estimation of Deck-Wetness for a High-Speed Vessel" for three years (1996 - 1998). The main conclusions obtained in this study are summarized as follows :(1)It was made clear that steady flow around a ship strongly affects unsteady hydrodynamic forces on a ship. We developed the new method predicting the interaction effect between them. It was made clear from this study that the second derivative term of steady flow potential plays important role on hydrodynamic forces.(2)We developed 3.D linear rankine panel method to predict the interaction effect between the steady and unsteady flow as a practical estimation method. Furthermore, it was made clear from the comparison with experimental results that this method was useful for predicting the seakeeping qualities of a high-speed vessel.(3)The steady flow strongly affects on radiation forces rather than diffraction forces. In particular, it strongly appears on them in the low frequen … More cy range.(4)The influence of steady flow has to be taken into account not only the free surface condition but also the ship hull surface condition to estimate accurately the pressure distribution on a ship.(5)The amplitudes of diffraction waves at bow part can be reduced by the knuckle at bow part. Thereby it is desirable to attach the knuckle at bow part to decrease the deck wetness on a high. speed vessel.(6)The influence between steady flow and unsteady flow becomes more remarkable as the forward speed increases. In particular, wave profile around bow part is strongly affected by the bow flare form. Thereby, It is necessary to develop a new predicting method which can take into account the effect of bow flare form above the still water surface in order to predict accurately seakeeping qualities of a high-speed vessel.(7)It was made clear that most of accidents for high-speed vessels are strongly related to unstable motions of high-speed vessels. Thereby, it is urgent to make clear hydrodynamic phenomena generating the unstable motions. Less