Research of the Effect of Encounter Frequency Scattering of Ships on the Response of Single Degree of Freedom Oscillatory Motions

In this study, for the encounter frequency change due to ship speed variation, the encounter frequency scattering model was established. The power spectrums of regular wave forces (or moments) were obtained by Fourier transformer for the case of encounter frequency scattering. The concept of encounter frequency scattering was interpreted in theory. Ship oscillatory motion equations of second-order dynamic system with single degree of freedom were solved through numerical simulation method. After the occurrence of encounter frequency scattering, the phenomenon of irregular oscillatory responses was verified. The relationship between the oscillatory motions variance and the scattering intensity of encounter frequency was examined by computing. The conclusions with respect to encounter frequency scattering are very important on theoretic research and underlying practical application.