Effect of partially filled spherical cargo tanks on the roll response of a bargelike vessel

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Abstract

Floating liquefied natural gas (FLNG) is an offshore structure which enables liquefaction, storage, and offloading of natural gas. It is a game changer in offshore hydrocarbon development. Side-by-side offloading is a promising way of transferring liquefied natural gas (LNG) from FLNG to an LNG carrier. The roll response of LNG carriers, which plays a critical role, has been observed to be influenced by the liquid cargo motion inside the tanks. Therefore, the operational window for side-by-side offloading may not be estimated robustly using a simplified method which ignores the liquid cargo and considers only the ballast condition. This necessitates a scientific understanding of the roll responses of an LNG carrier at different load conditions. In this study, a series of model tests are conducted on a bargelike vessel with two spherical tanks. The response amplitude operators (RAOs) and response spectra of the vessel in different load conditions and different headings are investigated. The effect of intermediate cargo volumes on global roll response is, for the first time, examined for spherical cargo tanks. It is suggested that intermediate loading conditions with explicit inclusion of the effects of cargo sloshing is utilized in side-by-side operability studies to robustly ascertain offloading availability.
Original languageEnglish
Article number031601-1
JournalJournal of Offshore Mechanics and Arctic Engineering
Volume138
Issue number3
DOIs
Publication statusPublished - 2016

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Liquefied natural gas
Liquid sloshing
Offshore structures
Liquids
Liquefaction
Natural gas
Hydrocarbons
Availability
Floating liquefied natural gas

Cite this

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title = "Effect of partially filled spherical cargo tanks on the roll response of a bargelike vessel",
abstract = "Floating liquefied natural gas (FLNG) is an offshore structure which enables liquefaction, storage, and offloading of natural gas. It is a game changer in offshore hydrocarbon development. Side-by-side offloading is a promising way of transferring liquefied natural gas (LNG) from FLNG to an LNG carrier. The roll response of LNG carriers, which plays a critical role, has been observed to be influenced by the liquid cargo motion inside the tanks. Therefore, the operational window for side-by-side offloading may not be estimated robustly using a simplified method which ignores the liquid cargo and considers only the ballast condition. This necessitates a scientific understanding of the roll responses of an LNG carrier at different load conditions. In this study, a series of model tests are conducted on a bargelike vessel with two spherical tanks. The response amplitude operators (RAOs) and response spectra of the vessel in different load conditions and different headings are investigated. The effect of intermediate cargo volumes on global roll response is, for the first time, examined for spherical cargo tanks. It is suggested that intermediate loading conditions with explicit inclusion of the effects of cargo sloshing is utilized in side-by-side operability studies to robustly ascertain offloading availability.",
author = "Wenhua Zhao and F. McPhail and Mike Efthymiou",
year = "2016",
doi = "10.1115/1.4032658",
language = "English",
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journal = "Journal of Offshore Mechanics and Arctic Engineering",
issn = "0892-7219",
publisher = "ASME International",
number = "3",

}

TY - JOUR

T1 - Effect of partially filled spherical cargo tanks on the roll response of a bargelike vessel

AU - Zhao, Wenhua

AU - McPhail, F.

AU - Efthymiou, Mike

PY - 2016

Y1 - 2016

N2 - Floating liquefied natural gas (FLNG) is an offshore structure which enables liquefaction, storage, and offloading of natural gas. It is a game changer in offshore hydrocarbon development. Side-by-side offloading is a promising way of transferring liquefied natural gas (LNG) from FLNG to an LNG carrier. The roll response of LNG carriers, which plays a critical role, has been observed to be influenced by the liquid cargo motion inside the tanks. Therefore, the operational window for side-by-side offloading may not be estimated robustly using a simplified method which ignores the liquid cargo and considers only the ballast condition. This necessitates a scientific understanding of the roll responses of an LNG carrier at different load conditions. In this study, a series of model tests are conducted on a bargelike vessel with two spherical tanks. The response amplitude operators (RAOs) and response spectra of the vessel in different load conditions and different headings are investigated. The effect of intermediate cargo volumes on global roll response is, for the first time, examined for spherical cargo tanks. It is suggested that intermediate loading conditions with explicit inclusion of the effects of cargo sloshing is utilized in side-by-side operability studies to robustly ascertain offloading availability.

AB - Floating liquefied natural gas (FLNG) is an offshore structure which enables liquefaction, storage, and offloading of natural gas. It is a game changer in offshore hydrocarbon development. Side-by-side offloading is a promising way of transferring liquefied natural gas (LNG) from FLNG to an LNG carrier. The roll response of LNG carriers, which plays a critical role, has been observed to be influenced by the liquid cargo motion inside the tanks. Therefore, the operational window for side-by-side offloading may not be estimated robustly using a simplified method which ignores the liquid cargo and considers only the ballast condition. This necessitates a scientific understanding of the roll responses of an LNG carrier at different load conditions. In this study, a series of model tests are conducted on a bargelike vessel with two spherical tanks. The response amplitude operators (RAOs) and response spectra of the vessel in different load conditions and different headings are investigated. The effect of intermediate cargo volumes on global roll response is, for the first time, examined for spherical cargo tanks. It is suggested that intermediate loading conditions with explicit inclusion of the effects of cargo sloshing is utilized in side-by-side operability studies to robustly ascertain offloading availability.

U2 - 10.1115/1.4032658

DO - 10.1115/1.4032658

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JO - Journal of Offshore Mechanics and Arctic Engineering

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SN - 0892-7219

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