Numerical Simulation And Model Test On The Hydrodynamic Performance Of FPSOS Under Extreme Marine Conditions

Nowadays,FPSO is used in offshore engineering widely. The hydrodynamic performanceof FPSO has become a hot research topic of scholars.Numerical simulation and model test arethe most commonly used methods to predict the hydrodynamic performance of FPSO andverity the strength of the mooring system.With FPSO’ development to deep water field, themooring system of it takes more space, in particular the catenary mooring system of FPSO,which horizontal span can reach2to3times depth of water.In the limited size of offshoreengineering test basin is probably because of insufficient water depth and horizontalspan,which is not adequate to accommodate the complete mooring system in a suit modelscale,so the mooring system of FPSO must to be truncated with equivalent characteristicswhen the size of offshore engineering test basin’s size is limited.Firstly,the global response of a internal turret moored FPSO is investigated by numericalprocedure AQWA in this paper.The RAOs,QTFs,etc of FPSO under regular waves arecalculated by using three-dimensional potential flow theory in frequency domain.Then,thehydrodynamic performance of FPSO and the strength of the mooring system are analysed intime domain, which is under five hundred years monsoon conditions and five hundred yearstyphoon conditions.Secondly, because of the Harbin Engineering University offshore engineering test basin’sspan is insufficient to meet the the span of the mooring system model scale.To solve theproblem of the limited width of Harbin Engeering University’s basin,truncation method isperformed for the catenary mooring system of FPSO.The new parameters of the mooringsystem can be determined according to the truncation method,then compare the static resultsand dynamic results of the truncated mooring system with the results of the untruncatedmooring system by AQWA which can prove the truncation design is accurately.Thirdly,model tests of the internal turrent FPSO are performanced in the offshoreengineering basin of Harbin Engineering University,which include free decay tests ofFPSO,RAOs tests of FPSO under white noise wave and in-place tests of FPSO under fivehundred years monsoon conditions and five hundred years typhoon conditions.The tests’results which include the motion response of FPSO and the tesion of mooring system are agree well with the results of numerical simulation.Lastly,model tests of the green water on FPSO are performed in the basin.Two optimizedmethods which include increasing the height of the forecastle of FPSO and increasing the bowflare angle are designed to prevent green water of FPSO.Then compare the results of greenwater of optimizations with the results of previous model tests.In conlusion,the results of numerical simulation and model tests in this paper canprovide a good reference for offshore engeering research in the future.