抄録
In this study, the characteristics of rolling in head waves for a vessel with nonlinear GZ-curve, which includes parametric rolling, are investigated. Rolling is measured for systematically changed wave length and height under the same forward speed, which is service speed in heavy weather. As the results, the range of Te/Tø(Te and Tø are encounter wave period and roll natural period),when periodic rolling occurs, is wider than one of previous results by Taguchi et al1), and the range spreads out wider range of Te/Tø>0.5. Especially, in the range of Te/Tø>0.5, roll amplitude becomes large, and a periodic rolling occurs at large wave height.It is supposed that the result is caused by the effects of roll amplitude on roll natural period. Then, numerical simulations2) are carried out for some variation of GZ-curves to confirm the measured results. Additionally, roll measurements in superposed waves of two different wave periods and in the irregular wave with Pierson-Moskowitz spectrum are also carried out.
