船舶单自由度摇荡运动对遭遇频率散射的响应

Response of ship oscillatory motion of two order dynamics system to encounter frequency scattering

针对船舶单自由度二阶摇荡运动动力学系统,就船舶速度变化引起遭遇频率改变问题建立了遭遇频率散射模式;采用傅立叶变换波浪力(矩)的波形,得到了遭遇频率散射后的功率谱,从理论上进一步阐明了船舶遭遇频率散射理论概念;采用数值模拟计算方法,计算了单自由度二阶摇荡运动,进一步验证了遭遇频率散射后出现不规则摇荡运动的现象,计算得到了遭遇频率散射强度与摇荡运动方差的关系。

By adopting ship motion equation of two order dynamics system with single-freedom degree,a model of encounter frequency scattering was established to deal with variation in encounter frequency caused by change in ship speed.For the encounter frequency scattering,a power spectrum of regular wave force was obtained by Fourier transformation.The spectrum clearly shows the response to other frequencies and further explains the concept of encounter frequency scattering.The adoption of the numerical simulation method to calculate the ship motion of two order dynamics system with single-freedom degree can further demonstrate the phenomenon of irregular oscillatory response after the encounter frequency scattering occurs and obtain the relation between the oscillatory motion variance and the intensity of encounter frequency scattering.