The seakeeping behavior of a vessel in multi-directional wave differs significantly from that in uni-directional wave. Given that a vessel operates in multi-directional or short-crested waves during its whole service period, it is important to have a better understanding of the influence of wave directionality on ship seakeeping performance. In this study, CFD method is used to simulate ship motions in both uni- and bi-directional regular waves. A S175 hull model is adopted for seakeeping analysis. Both uni- and bi-directional waves are generated by velocity boundary method. Overset grid technique is adopted to simulate ship motions in waves. Ship motions in different uni-directional regular wave conditions are predicted and validated by experimental data at first. Then ship motions in monochromatic bi-directional wave conditions with different control parameters such as wave length, ship speed and ship heading angle are predicted and analyzed. The comparative results indicate that ship motion response in bi-directional waves is generally larger than that in uni-directional waves. Moreover, severe bow slamming and green water under bi-directional waves are also observed and investigated. This study indicates that ship seakeeping behavior in bi-directional wave should be paid enough attention during ship design and evaluation.

船舶在多向波浪中的航海行为与单向波浪中的航海行为显着不同。鉴于船舶在整个服役期间均以多方向或短波状航行，因此重要的是要更好地了解波浪方向性对船舶海上航行性能的影响。在这项研究中，CFD方法用于模拟单向和双向规则波中的船舶运动。采用S175船体模型进行航海分析。单向和双向波都是通过速度边界法产生的。采用过冲网格技术模拟船舶在波浪中的运动。首先，通过实验数据预测并验证了不同单向规则波条件下的船舶运动。然后，预测并分析了单色双向波条件下具有不同控制参数（例如波长，船速和船航向角）的船舶运动。比较结果表明，双向波中的船舶运动响应通常大于单向波中的船舶运动响应。此外，还观察到并研究了双向波浪作用下的严重船首砰击声和绿水现象。这项研究表明，在船舶设计和评估过程中应充分注意双向波浪中的船舶航行行为。还观察到并研究了严重的弓撞击和双向波浪下的绿水。这项研究表明，在船舶设计和评估过程中应充分注意双向波浪中的船舶航行行为。还观察到并研究了严重的弓撞击和双向波浪下的绿水。这项研究表明，在船舶设计和评估过程中应充分注意双向波浪中的船舶航行行为。