风浪联合作用下OOstar平台低频运动响应分析

基于FAST建立OOstar平台的时域模型,研究风浪联合作用下平台的运动响应,采用统计学方法分析平台的不规则运动规律,利用傅里叶变换对平台运动进行频谱分析,重点关注波浪载荷差频分量及风载荷对平台低频慢漂运动的影响。结果表明：在不同海况下差频分量与风载荷均会使平台运动振幅增加,并使大振幅对应运动周期的离散性增强,而对小振幅对应运动周期的影响较小;差频分量对振幅及运动周期的影响随着海况的恶劣而增强,风载荷则相反。频谱分析表明,差频分量在不同海况下对平台自振频率处运动的激励影响均较大,风载荷则在四级海况下对平台自振频率处运动的激励影响较大,在八级海况下对平台自振频率处的激励影响较小。

Analysis of OOstar Floating Platform Low Frequency Motion Under Wind and Wave Actions

Based on FAST, the time domain model of OOstar platform is established, and the response of the platform under the wind and wave actions are investigated. The distribution of random motion of the platform is analyzed by statistic method, and the spectra of platform motion are calculated by Fourier transform, especially focusing on the impact of wave difference frequency force and wind load on the low frequency slow drift motion. The results indicate that: the wave difference frequency force and wind load will increase the amplitude of the platform, and strengthen the discreteness of periods related to big-amplitude motion, while are of little influence on the periods corresponded to small-amplitude motion; the influences of difference frequency force on the amplitude and period increase as the wave states getting worse, while the influences of wind loads are opposite. The spectrum analysis indicates that the difference frequency force stimulates the platform response at its natural frequency under different sea conditions, while the influence of wind load is obvious only at the fourth wave state.