中文摘要：

研究纵浪中船舶初稳性高时变特性对横摇运动的影响。假设升沉和纵摇是准静力平衡,建立纵浪中船舶横摇参数激励运动方程,提出了稳性高波动项与瞬时波浪高度及波面升高加速度之间的函数关系式,提供了稳性高波动项的计算方法。以一艘渔政船为例,在不同航速下,分别计算规则波和非规则波中船舶参数激励横摇运动。得到稳性高波动项的时间历程及功率谱,并模拟由初稳性高随机波动引起的参数激励横摇。结果表明：在船遭遇一系列高波情况下,当特征波长接近船长,且参数激励频率集中在二倍横摇固有频率时,船舶发生参数激励大幅横摇。

英文摘要：

The influence of metacentric height fluctuations on roll motion of ships in longitudinal seas is researched. The parametrically excited ship rolling differential equation in longitudinal seas is built by assuming quasi-static equilibrium of heave and pitch motions. A formulation for metacentric height fluctuations is derived in terms of instantaneous wave elevations and wave elevation accelerations. The parametrically excited roll responses are illustrated in the case of a fisher-manage vessel in regular and irregular waves. The matacentric height fluctuations are simulated as stochastic processes at different speed, and the metacentric height spectra are obtained by using the Fourier transform. The roll motions which are induced by stochastic metacentric height fluctuations are also simulated. The numerical results shows that when a ship encounters series of high waves in longitudinal seas the parametric rolling will occur in the conditions that the wave length is near the ship length and the parametrical excitation frequency is near the twice of natural roll frequency.