Study On Side-by-side Berthing Of Floating Storage-re-gasification Unit And LNG Carrier

Due to the rapid development of the economy,the international trade and transportation of natural gas arises.Maritime transportation via LNG vessels is the main mode of natural gas transportation.In the past,natural gas terminals are usually placed on land area of the port,which are heavily invested,inefficient and easy to cause public security problem.Therefore Floating Storage and Re-gasification Unit(FSRU)get the favor of more and more managers.However,the history of FSRU is only around a decade.Practical engineering experience are far from enough to offer guidance in the process of construction for such form of transportation,and there are still problems to be solved.Based on numerical simulations using a model based on the three-dimensional potential theory,the present thesis focuses on sensitivity analysis of the dynamic characteristics of a side-by-side mooring FSRU-LNGC and a single ship.The first part of this thesis is the calculation of frequency domain for the selected vessels.Without considering the mooring facilities,wind and current condition and the displacement of ship,the hydrodynamic characteristics of the ship were analyzed for the cases of different water depths and wave directions.The main parts of the research cover the response amplitude,additional mass and radiation damping of ship.The second part is the time-domain analysis.By setting up the conditions of wind,wave and flow,the result of the motion of ship,cable force and fender force are calculated,which were compared with physical experiment for verification of the model.Then further analysis was carried out to give some suggestions about the layout of cable and the direction choice of terminal.Under the action of wind waves,the main difference between a side-by-side mooring ship system and a single mooring ship is that the single ship system is more stable under head waves,while is the opposite under beam waves.The bow and stern cables of the LNGC moored to the piers can provide better results of the mooring system.In the condition of head wave,the ships have not considerable motions in long period wave.In the condition of oblique wave,the ship’s motions,such as surge,roll and yaw grow rapidly with the increase of wave period.In the condition of transverse wave,the ship’s movements,such as surge and roll are significant,and the roll resonance occurs at the wave period of 15 s.