Hydrodynamics of an FLNG system in tandem offloading operation

Floating liquefied natural gas (FLNG) is a new type of offshore platform that consists of a ship-type floating production storage and offloading (FPSO) hull equipped with LNG storage tanks and liquefaction plants. In LNG offloading operation, tandem configuration where LNG carrier connects to the stern of an FLNG, shows its prospects. In this study, the hydrodynamic characteristics of a single point turret-moored FLNG system in tandem offloading operation are investigated by using a time-domain coupled dynamic analysis program and a set of comparative model tests. The numerical simulation model features well the hydrodynamic performance of the coupled system obtained from the experiments. The influence of distance between the two vessels on their hydrodynamic performance has been investigated. Furthermore, two different ways of connecting FLNG vessel and LNG carrier have also been comparatively studied. The numerical results show that there is significant difference at the hydrodynamic performance in the two ways of tandem offloading operations, which means that the connection between FLNG vessel and LNG carrier plays an important role. The outcome of this study would offer better understanding on the hydrodynamics of multi-bodies, which can further lead to more practical applications for the design and operation of FLNG.

► The hydrodynamic performance of an FLNG system in tandem offloading operation has been investigated using numerical simulations and scaled model tests.
► The coupled dynamic analysis model considering the vessels, turret mooring systems, connected hawsers and their mutual interactions is established and features well the experimental measurements.
► The effects of the connection ways and the distances between the two vessels on their hydrodynamics have been clarified, providing useful information on the design and operation of an FLNG system.