Robust prediction of extreme motions during wind farm support vessel(WFSV)operation is an important safety concern that requires further extensive research as offshore wind energy industry sector widens.In particular,...Robust prediction of extreme motions during wind farm support vessel(WFSV)operation is an important safety concern that requires further extensive research as offshore wind energy industry sector widens.In particular,it is important to study the safety of operation in random sea conditions during WFSV docking against the wind tower,while workers are able to get on the tower.Docking is performed by thrusting vessel fender against wind tower(an alternative docking way by hinging is not studied here).In this paper,the finite element software AQWA has been used to analyze vessel response due to hydrodynamic wave loads,acting on a specific maintenance ship under actual sea conditions.Excessive roll may occur during certain sea conditions,especially in the beam sea,posing a risk to the crew transfer operation.The Bohai Sea is the area of diverse industrial activities such as offshore oil production,wave and wind power generation,etc.This paper advocates a novel method for estimating extreme roll statistics,based on Monte Carlo simulations(or measurements).The ACER(averaged conditional exceedance rate)method and its modification are presented in brief detail in Appendix.The proposed methodology provides an accurate extreme value prediction,utilizing available data efficiently.In this study the estimated return level values,obtained by ACER method,are compared with the corresponding return level values obtained by Gumbel method.Based on the overall performance of the proposed method,it is concluded that the ACER method can provide more robust and accurate prediction of the extreme vessel roll.The described approach may be well used at the vessel design stage,while defining optimal boat parameters would minimize potential roll.展开更多
为了解海洋石油支持船(Offshore Support Vessel-OSV)抛锚作业过程中,系泊缆和工作缆的缆型、张力变化以及抛锚作业对锚作船的影响,提出了一种OSV抛锚作业的建模方法。采用MMG(Ship Manoeuvring Mathematical Model Group)建模思想,建...为了解海洋石油支持船(Offshore Support Vessel-OSV)抛锚作业过程中,系泊缆和工作缆的缆型、张力变化以及抛锚作业对锚作船的影响,提出了一种OSV抛锚作业的建模方法。采用MMG(Ship Manoeuvring Mathematical Model Group)建模思想,建立了六自由度拖船运动数学模型,通过水下缆索任一微元段的受力平衡条件导出各微元段的动力学微分方程,建立了拖缆模型。在此基础上考虑耦合边界条件,建立了船-缆-锚-缆系统的运动数学模型,并采用龙格库塔方法对船舶运动积分求解,采用差分法对拖缆运动进行求解。仿真结果表明该模型可为制定抛锚控制策略提供参考依据,并对OSV模拟器开发提供理论基础。展开更多
文摘Robust prediction of extreme motions during wind farm support vessel(WFSV)operation is an important safety concern that requires further extensive research as offshore wind energy industry sector widens.In particular,it is important to study the safety of operation in random sea conditions during WFSV docking against the wind tower,while workers are able to get on the tower.Docking is performed by thrusting vessel fender against wind tower(an alternative docking way by hinging is not studied here).In this paper,the finite element software AQWA has been used to analyze vessel response due to hydrodynamic wave loads,acting on a specific maintenance ship under actual sea conditions.Excessive roll may occur during certain sea conditions,especially in the beam sea,posing a risk to the crew transfer operation.The Bohai Sea is the area of diverse industrial activities such as offshore oil production,wave and wind power generation,etc.This paper advocates a novel method for estimating extreme roll statistics,based on Monte Carlo simulations(or measurements).The ACER(averaged conditional exceedance rate)method and its modification are presented in brief detail in Appendix.The proposed methodology provides an accurate extreme value prediction,utilizing available data efficiently.In this study the estimated return level values,obtained by ACER method,are compared with the corresponding return level values obtained by Gumbel method.Based on the overall performance of the proposed method,it is concluded that the ACER method can provide more robust and accurate prediction of the extreme vessel roll.The described approach may be well used at the vessel design stage,while defining optimal boat parameters would minimize potential roll.
文摘为了解海洋石油支持船(Offshore Support Vessel-OSV)抛锚作业过程中,系泊缆和工作缆的缆型、张力变化以及抛锚作业对锚作船的影响,提出了一种OSV抛锚作业的建模方法。采用MMG(Ship Manoeuvring Mathematical Model Group)建模思想,建立了六自由度拖船运动数学模型,通过水下缆索任一微元段的受力平衡条件导出各微元段的动力学微分方程,建立了拖缆模型。在此基础上考虑耦合边界条件,建立了船-缆-锚-缆系统的运动数学模型,并采用龙格库塔方法对船舶运动积分求解,采用差分法对拖缆运动进行求解。仿真结果表明该模型可为制定抛锚控制策略提供参考依据,并对OSV模拟器开发提供理论基础。
