Nonlinear Hydrodynamic Analysis and Large-amplitude Motion Prediction of Ships in Time Domain Based on Multi-domain Method

On the basis of the improvement of internal and external domain calculation, Dr. Chris Mellenie proposed a multi-domain method (MDHOBEM＿HOS) for generating incident waves based on the Higher Order Spectrum,HOS) method. Compared with the previous research, this method not only considers the "ship-wave" interaction, but also considers the wave evolution and its nonlinearity, that is, the "wave-wave" interaction. The numerical simulation shows that the wave field generated by HOS is obviously nonlinear compared with the linear wave field. Taking three ship types (S175,S60 and an inclining ship) with different appearance characteristics as the objects, the MDHOBEM＿HOS method can better capture the nonlinear phenomenon when calculating the ship motion response in nonlinear waves, and it has more advantages in predicting the motion (such as parametric rolling) in dangerous and extreme working conditions. Based on the three-dimensional potential flow theory, the multi-domain method is improved from three levels: internal domain, external domain and wave excitation, and different levels of numerical calculation models of ship hydrodynamics are put forward, forming a set of systematic, accurate, stable, efficient and widely applicable methods for studying and analyzing ship motion and its application, which has important research and engineering practical value.

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