Application of the Seakeeping / Sloshing Coupling For the LNG Terminals Available to Purchase

The proposed paper deals with Bureau Veritas methodology and procedures for the analysis of hydrodynamic and sloshing responses of LNG vessels operating as LNG terminals in wide range of operational conditions. The particular application covers external wave loading and internal sloshing loading in LNG cargo tanks, including the dynamic effects of their mutual hydrodynamic interaction. Sloshing feasibility analysis is the core of Bureau Veritas sloshing assessment. State of the art of sloshing analysis relies on small-scale sloshing model tests supported by extensive developments of CFD computation techniques, commonly studying one isolated tank submitted to the forced motion without their mutual interaction. In reality, wave-induced response of the vessel carrying liquid cargo is affected by internal liquid motion, and consequently, tank liquid flow is altered by the vessel motion in return. This paper presents various aspects of such seakeeping/sloshing coupling, addressing among the other BV developments of efficient numerical tool to predict this dynamic coupling, the influence on transverse first order motions identified by experimental campaigns, validation of these numerical models through experiments such as measurement of the global forces exerted by the moving fluid in the tank and dedicated wave basin tests where the hull and the tanks are modeled. The influence of hydrodynamic coupling is illustrated through the application for various LNG terminal projects; from currently operating LNG RVs (Liquified Natural Gaz Regasification Vessel) over the potential conversion of existing ships in service to the new buildings of LNG FPSOs (Floating Production Storage and Offloading) or LNG FSRUs (Floating Storage and Regasification Unit) and for different tanks' arrangements.