桁架式Spar平台与系泊/立管系统的全时域非线性耦合动态分析
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摘要
开发了对浮式平台系统进行耦合动态分析的全时域程序。采用二阶时域方法计算水动力荷载,在此方法中,对物面边界条件和自由水面边界条件进行泰勒级数展开,利用Stokes摄动展开分别建立相应的一阶、二阶边值问题,而且此边值问题的计算域不随时间变化。采用高阶边界元方法计算每一时刻流场中的速度势,利用四阶预报校正法对二阶自由水面边界条件进行数值积分。在自由表面加入一个人工阻尼层来避免波浪的反射。对于系泊缆索/立管/张力腿的动力分析,在一个总体坐标系中对控制方程进行描述,采用基于细长杆理论的有限元方法进行求解。在耦合动态分析中,采用Newmark方法对平台和系泊缆索/立管/张力腿的运动方程同时进行求解。利用开发的耦合分析程序对一个桁架式Spar平台的运动响应进行了数值模拟,给出了平台的位移和系泊缆索/立管上端点的张力,并得到了一些重要结论。
A full time-domain program is developed for the coupled dynamic analysis of floating platform systems. For the hydrodynamic loads, a time domain second order method is developed. In this approach,Taylor series expansions are applied to the body surface and free-surface boundary conditions, and Stokes perturbation procedure is used to establish corresponding first-order and second-order boundary value problems with time-independent boundaries. A higher-order boundary element method(HOBEM) is developed to calculate the velocity potential of the resulting flow field at each time step. The free-surface boundary condition is satisfied to the second order by 4th order Adams-Bashforth-Moultn method. An artificial damping layer is adopted on the free surface to avoid the wave reflection. The mooring-line/tendon/riser dynamics are based on a rod theory and finite element method(FEM), with the governing equations described in a global coordinate system. In the coupled dynamic analysis, the motion equation for the hull and dynamic equations for mooring-lines/tendons/risers are solved simultaneously using Newmark method. The coupled analysis program is applied for a Truss Spar motion response simulation. Numerical results including hull motions and tensions at the top of mooring-lines/risers are presented, and some significant conclusions are derived.
A full time-domain program is developed for the coupled dynamic analysis of floating platform systems. For the hydrodynamic loads, a time domain second order method is developed. In this approach,Taylor series expansions are applied to the body surface and free-surface boundary conditions, and Stokes perturbation procedure is used to establish corresponding first-order and second-order boundary value problems with time-independent boundaries. A higher-order boundary element method(HOBEM) is developed to calculate the velocity potential of the resulting flow field at each time step. The free-surface boundary condition is satisfied to the second order by 4th order Adams-Bashforth-Moultn method. An artificial damping layer is adopted on the free surface to avoid the wave reflection. The mooring-line/tendon/riser dynamics are based on a rod theory and finite element method(FEM), with the governing equations described in a global coordinate system. In the coupled dynamic analysis, the motion equation for the hull and dynamic equations for mooring-lines/tendons/risers are solved simultaneously using Newmark method. The coupled analysis program is applied for a Truss Spar motion response simulation. Numerical results including hull motions and tensions at the top of mooring-lines/risers are presented, and some significant conclusions are derived.
引文
[1]Ma W,Lee M Y,Zou J,Huang E.Deepwater nonlinear coupled analysis tool[C]//In:Proceedings of the Offshore Technology Conference,OTC 12085.Houston,Texas,2000.
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[7]Garrett D L.Coupled analysis of floating production systems[J].Ocean Engineering,2005,32:802-816.
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[10]Low Y M,Langley R S.A hybrid time/frequency domain approach for efficient coupled analysis of vessel/mooring/riser dynamics[J].Ocean Engineering,2008,35(5-6):433-446.
[11]Chen X,Ding Y,Zhang J,Liagre P,Niedzwecki J,Teigen P.Coupled dynamic analysis of a mini TLP:Comparison with measurements[J].Ocean Engineering,2006,33(1):93-117.
[12]Zhang F,Yang J,Li R,Chen G.Coupling effects for cell-truss Spar platform:Comparison of frequency-and time-domain analyses with model tests[J].Journal of Hydrodynamics,2008,20(4):424-432.
[13]de Kat J O,Dercksen A.The influence of wave spectrum formulation on the dynamics of a turret-moored tanker[J].Journal of Offshore Mechanics and Arctic Engineering,1994,116:7-13.
[14]Ran Z,Kim M H.Nonlinear coupled responses of a tethered Spar platform in waves[J].International Journal of Offshore and Polar Engineering,1997,7(2):111-118.
[15]Ormberg H,Larsen K.Coupled analysis of floating motion and mooring dynamics for a turret moored tanker[J].BOSS,1997,2:469-483.
[16]Ran Z,Kim M H,Zheng W.Coupled dynamic analysis of a moored Spar in random waves and currents(time-domain vs frequency-domain analysis)[C].In:Proceedings of the 17th OMAE Conference,OMAE-0604,1998.
[17]Ormberg H,Sodahl N,Steinkjer O.Efficient analysis of mooring systems using de-couple and coupled analysis[C].In:Proceedings of the 17th OMAE Conference,OMAE-0351,1998.
[18]Tahar A,Halkyard J,Irani M.Comparison of time and frequency domain analysis with full scale data for the horn mountain Spar during Hurricane Isidore[C]//In:Proceedings of the Twenty fifth Offshore Mechanics and Artic Engineering Conference.Hamburg,Germany,2006.
[19]Yang C K,Kim M H.Transient effect of tendon disconnection of a TLP by hull-tendon-riser coupled dynamic analysis[J].Ocean Engineering,2010,37:667-677.
[20]Teng B,Yang M.Nonlinear coupled dynamic analysis for waves and a moored platform in time domain[C]//The 26th International Workshop on Water Waves and Floating Bodies.Athens,Greece,2011.
[21]Isaacson M,Ng J Y T.Second-order wave radiation of three-dimensional bodies by time-domain method[J].Int.J Offshore of Polar Eng.,1993,3(4):264-272.
[22]Garrett D L.Dynamic analysis of slender rods[J].Journal of Energy Resources Technology,Transactions of ASME,1982,104:302-307.
[23]Kim C H,Kim M H,Liu Y H,Zhao C T.Time domain simulation of nonlinear response of a coupled tlp system[J].Int.J Offshore of Polar Eng.,1994,4(4):284-291.
[2]Lee M Y,Flory J.ABS guide for synthetic ropes in offshore mooring applications[C]//In:Proc.Offshore Technology Conference,OTC 10910.Houston,Texas,1999.
[3]Lee M Y,Devlin P.Development of API RP 2SM for synthetic fiber rope moorings[C]//Proc.Offshore Technology Conference,OTC 12178.Houston,Texas,2000.
[4]Kim M H,Tahar A,Kim Y B.Variability of Spar motion analysis against various design methodologies/parameters[C]//In:Proceedings of the Twentieth Offshore Mechanics and Artic Engineering Conference,OMAE01-OFT1063.Rio de Janeiro,Brazil,2001a.
[5]Kim M H,Tahar A,Kim Y B.Variability of TLP motion analysis against various design methodologies/parameters[C]//In:Proceedings of the International Offshore and Polar Engineering Conference,ISOPE 3.Stavanger,Norway,2001b.
[6]Ran Z.Coupled dynamic analysis of floating structures in waves and current[D].Ph.D dissertation,Texas A and M University,2000.
[7]Garrett D L.Coupled analysis of floating production systems[J].Ocean Engineering,2005,32:802-816.
[8]Kim M H,Koo B J,Mercier R M,Ward E G.Vessel/mooring/riser coupled dynamic analysis of a turret-moored FPSO compared with OTRC experiment[J].Ocean Engineering,2005,32:1780-1802.
[9]Tahar A,Kim M H.Coupled-dynamic analysis of floating structures with polyester mooring lines[J].Ocean Engineering,2008,35:1676-1685.
[10]Low Y M,Langley R S.A hybrid time/frequency domain approach for efficient coupled analysis of vessel/mooring/riser dynamics[J].Ocean Engineering,2008,35(5-6):433-446.
[11]Chen X,Ding Y,Zhang J,Liagre P,Niedzwecki J,Teigen P.Coupled dynamic analysis of a mini TLP:Comparison with measurements[J].Ocean Engineering,2006,33(1):93-117.
[12]Zhang F,Yang J,Li R,Chen G.Coupling effects for cell-truss Spar platform:Comparison of frequency-and time-domain analyses with model tests[J].Journal of Hydrodynamics,2008,20(4):424-432.
[13]de Kat J O,Dercksen A.The influence of wave spectrum formulation on the dynamics of a turret-moored tanker[J].Journal of Offshore Mechanics and Arctic Engineering,1994,116:7-13.
[14]Ran Z,Kim M H.Nonlinear coupled responses of a tethered Spar platform in waves[J].International Journal of Offshore and Polar Engineering,1997,7(2):111-118.
[15]Ormberg H,Larsen K.Coupled analysis of floating motion and mooring dynamics for a turret moored tanker[J].BOSS,1997,2:469-483.
[16]Ran Z,Kim M H,Zheng W.Coupled dynamic analysis of a moored Spar in random waves and currents(time-domain vs frequency-domain analysis)[C].In:Proceedings of the 17th OMAE Conference,OMAE-0604,1998.
[17]Ormberg H,Sodahl N,Steinkjer O.Efficient analysis of mooring systems using de-couple and coupled analysis[C].In:Proceedings of the 17th OMAE Conference,OMAE-0351,1998.
[18]Tahar A,Halkyard J,Irani M.Comparison of time and frequency domain analysis with full scale data for the horn mountain Spar during Hurricane Isidore[C]//In:Proceedings of the Twenty fifth Offshore Mechanics and Artic Engineering Conference.Hamburg,Germany,2006.
[19]Yang C K,Kim M H.Transient effect of tendon disconnection of a TLP by hull-tendon-riser coupled dynamic analysis[J].Ocean Engineering,2010,37:667-677.
[20]Teng B,Yang M.Nonlinear coupled dynamic analysis for waves and a moored platform in time domain[C]//The 26th International Workshop on Water Waves and Floating Bodies.Athens,Greece,2011.
[21]Isaacson M,Ng J Y T.Second-order wave radiation of three-dimensional bodies by time-domain method[J].Int.J Offshore of Polar Eng.,1993,3(4):264-272.
[22]Garrett D L.Dynamic analysis of slender rods[J].Journal of Energy Resources Technology,Transactions of ASME,1982,104:302-307.
[23]Kim C H,Kim M H,Liu Y H,Zhao C T.Time domain simulation of nonlinear response of a coupled tlp system[J].Int.J Offshore of Polar Eng.,1994,4(4):284-291.