A computer code based on the double-body potential flow model and the classic source panel method has been developed to study various problems of hydrodynamic interaction between ships and other objects with solid bou...A computer code based on the double-body potential flow model and the classic source panel method has been developed to study various problems of hydrodynamic interaction between ships and other objects with solid boundaries including the seabed. A peculiarity of the proposed implementation is the application of the so-called ＂moving-patch＂ method for simulating steady boundaries of large extensions. The method is based on an assumption that at any moment just the part of the boundary （＂moving patch＂） which lies close to the interacting ship is significant for the near-field interaction. For a specific case of the fiat bottom, comparative computations were performed to determine optimal dimensions of the patch and of the constituting panels based on the trade-off between acceptable accuracy and reasonable efficiency. The method was applied to estimate the sway force on a ship hull moving obliquely across a dredged channel. The method was validated for a case of ship-to-ship interaction when tank data were available. This study also contains a description of a newly developed spline approximation algorithm necessary for creating consistent discretizations of ship hulls with various degrees of refinement.展开更多
The seakeeping performance of a luxury cruise ship was evaluated during the concept design phase.By comparing numerical predictions based on 3-D linear potential flow theory in the frequency domain with the results of...The seakeeping performance of a luxury cruise ship was evaluated during the concept design phase.By comparing numerical predictions based on 3-D linear potential flow theory in the frequency domain with the results of model tests, it was shown that the 3-D method predicted the seakeeping performance of the luxury cruise ship well.Based on the model, the seakeeping features of the luxury cruise ship were analyzed, and then the influence was seen of changes to the primary design parameters (center of gravity, inertial radius, etc.).Based on the results, suggestions were proposed to improve the choice of parameters for luxury cruise ships during the concept design phase.They should improve seakeeping performance.展开更多
为揭示船舶在追越过程中碰撞危险演化特征,提出一种基于情景反演的碰撞风险推理方法。基于追越事故案例中记录的船舶碰撞过程的动态信息,反演船舶追越过程中碰撞危险信息;引入负指数函数,结合船舶属性,通过最近会遇距离(Distance of Clo...为揭示船舶在追越过程中碰撞危险演化特征,提出一种基于情景反演的碰撞风险推理方法。基于追越事故案例中记录的船舶碰撞过程的动态信息,反演船舶追越过程中碰撞危险信息;引入负指数函数,结合船舶属性,通过最近会遇距离(Distance of Closest Point of Approach,d_(CPA))与两船到达最近会遇距离的时间(Time to Closest Point of Approach,t_(CPA))无因次化,确立船舶会遇的碰撞危险度(Collision Risk Index,I_(CR)),运用灰云推理模型,提出时间维度下追越两船的碰撞风险推理(Potential Collision Risk,P_(CR));结合多起案例反演数据,得出船舶追越过程中P_(CR)特征。结果表明:船舶追越依次经过碰撞危险、紧迫局面和紧迫危险等3个阶段,在时间节点上有一定稳定性特征,对应的P_(CR)均值分别为0.3491、0.5575和0.7771;船舶左舷追越的P_(CR)值略大于右舷追越;让路船的P_(CR)值感知也略大于直航船。基于情景反演的碰撞风险推理方法能反映会遇过程中两船实时的碰撞风险,为驾驶员实施精细化避碰行动提供有效理论支撑。展开更多
基金Supported by the Portuguese Foundation for Science and Technology under Grant No.PTDC/ECM/100686/2008
文摘A computer code based on the double-body potential flow model and the classic source panel method has been developed to study various problems of hydrodynamic interaction between ships and other objects with solid boundaries including the seabed. A peculiarity of the proposed implementation is the application of the so-called ＂moving-patch＂ method for simulating steady boundaries of large extensions. The method is based on an assumption that at any moment just the part of the boundary （＂moving patch＂） which lies close to the interacting ship is significant for the near-field interaction. For a specific case of the fiat bottom, comparative computations were performed to determine optimal dimensions of the patch and of the constituting panels based on the trade-off between acceptable accuracy and reasonable efficiency. The method was applied to estimate the sway force on a ship hull moving obliquely across a dredged channel. The method was validated for a case of ship-to-ship interaction when tank data were available. This study also contains a description of a newly developed spline approximation algorithm necessary for creating consistent discretizations of ship hulls with various degrees of refinement.
文摘The seakeeping performance of a luxury cruise ship was evaluated during the concept design phase.By comparing numerical predictions based on 3-D linear potential flow theory in the frequency domain with the results of model tests, it was shown that the 3-D method predicted the seakeeping performance of the luxury cruise ship well.Based on the model, the seakeeping features of the luxury cruise ship were analyzed, and then the influence was seen of changes to the primary design parameters (center of gravity, inertial radius, etc.).Based on the results, suggestions were proposed to improve the choice of parameters for luxury cruise ships during the concept design phase.They should improve seakeeping performance.
文摘为揭示船舶在追越过程中碰撞危险演化特征,提出一种基于情景反演的碰撞风险推理方法。基于追越事故案例中记录的船舶碰撞过程的动态信息,反演船舶追越过程中碰撞危险信息;引入负指数函数,结合船舶属性,通过最近会遇距离(Distance of Closest Point of Approach,d_(CPA))与两船到达最近会遇距离的时间(Time to Closest Point of Approach,t_(CPA))无因次化,确立船舶会遇的碰撞危险度(Collision Risk Index,I_(CR)),运用灰云推理模型,提出时间维度下追越两船的碰撞风险推理(Potential Collision Risk,P_(CR));结合多起案例反演数据,得出船舶追越过程中P_(CR)特征。结果表明:船舶追越依次经过碰撞危险、紧迫局面和紧迫危险等3个阶段,在时间节点上有一定稳定性特征,对应的P_(CR)均值分别为0.3491、0.5575和0.7771;船舶左舷追越的P_(CR)值略大于右舷追越;让路船的P_(CR)值感知也略大于直航船。基于情景反演的碰撞风险推理方法能反映会遇过程中两船实时的碰撞风险,为驾驶员实施精细化避碰行动提供有效理论支撑。
