Abstract
The present paper does an experimental and numerical investigation of the hydrodynamic interaction and the response of a single point turret-moored Floating Liquefied Natural Gas (FLNG) system, which is a new type of floating LNG (Liquid Natural Gas) platform that consists of a ship-type FPSO hull equipped with LNG storage tanks and liquefaction plants. In particular, this study focuses on the investigation of the roll response of FLNG hull in free-decay motions, white noise waves and also in irregular waves. Model tests of the FLNG system in 60%H filling condition excited by both white noise waves and irregular waves combined with steady wind and current have been carried out. Response Amplitude Operators (RAOs) and time histories of the responses are obtained for sway, roll and yaw motions. Obvious Low Frequency (LF) components of the roll motions are observed, which may be out of expectation. To facilitate the physical understanding of this phenomenon, we filter the roll motions at the period of 30 s into two parts: the Wave Frequency (WF) motions and the Low Frequency (LF) motions respectively. The results indicate that the LF motions are closely related to the sway and yaw motions. Possible reasons for the presence of the LF motions of roll have been discussed in detail, through the comparison with the sway and yaw motions. As for the numerical part, the simulation of the modeled case is conducted with the help of the software SESAM®. A good agreement between experiments and calculations is reported within the scope of trends. However, the numerical simulations should be further improved for the prediction of the FLNG system in the heading sea.
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References
International Energy Agency. World Energy Outlook 2010, 2010
Yu Y H, Kinnas S A. Roll response of ship-shaped hulls in waves. In: Proc. of 28th International Conference on Offshore Mechanics and Arctic Engineering, Honolulu, Hawaii, USA, 2009. OMAE 2009-80043
Vugts J H. The Hydrodynamic Coefficients for Swaying, Heaving and Rolling Cylinders in a Free Surface. Rept. No. 194, Laboratorium voor Scheepsboukunde, Technische Hogeschool Delft, The Netherlands, 1968
Himeno Y. Prediction of Ship Roll Damping-A State of the Art. Rept. No. 239, University of Michigan at Ann Arbor, Department of Naval Architecture, 1981
Taz Ul Mulk M, Falzarano J. Complete six-degrees-of-freedom nonlinear ship rolling motion. Trans Am Soc Mech Eng J Offshore Mech Arct Eng, 1994, 116: 191–191
Alessandrini B, Delhommeau G. Simulation of 3-dimensional unsteady viscous free-surface flow around a ship model. Int J Numer Methods Fluids, 1994, 19 (4): 321–342
Yeung R W, Liao S W, Roddier D. On roll hydrodynamics of rectangular cylinders. In: International Offshore and Polar Engineering Conference, ISOPE, Montreal, Can, 1998. 445–453
Na J H, Lee W C, Shin H S, et al. A design of bilge keels for harsh environment FPSOs. International Offshore and Polar Engineering Conference, ISOPE, Kitakyushu, Japan, 2002. 114–117
Seah R K M, Yeung R W. Sway and roll hydrodynamics of cylindrical sections. International Offshore and Polar Engineering Conference, ISOPE, Honolulu, HI, United States, 2003. 1861–1868
Tahara Y, Longo J, Stern F, et al. Comparison of CFD and EFD for the Series 60 CB = 0.6 in steady yaw motion. In: Proceedings of the 22nd ONR Symposium on Naval Hydrodynamics, Washington, DC, 1998
Hochbaum A, Vogt M. Towards the simulation of seakeeping and maneuvering based computation of the free surface viscous ship flow. In: Proceedings of the 24th ONR Symposium on Naval Hydrodynamics, Fukuoka, Japan, 2002
Simonsen C D, Stern F. RANS maneuvering simulation of Esso Osaka with rudder and a body-force propeller. J Ship Res, 2005, 49(2): 98–120
Wilson R V, Carrica P M, Stern F. Unsteady RANS method for ship motions with application to roll for a surface combatant. Comput Fluids, 2006, 35(5): 501–524
Matos Vinícius L F, Ribeiro Eric O, Simos Alexandre N, et al. 2nd order pitch and roll slow motions of a semi-submersible platform: Full scale measurements and theoretical predictions comparative study. In: Proc. of 29th International Conference on Offshore Mechanics and Arctic Engineering, Shanghai, China, 2010. OMAE 2010-20898
Stansberg C T, Yttervik R, Øritsland O, et al. Hydrodynamic model test verification of a floating platform system in 3000m water depth. In: Proc. of 19th International Conference on Offshore Mechanics and Arctic Engineering, New Orleans, LA, USA, 2000. OMAE2000-4145
Stansberg C T, Øritsland O, Kleiven G. VERIDEEP: reliable methods for laboratory verification of mooring and stationkeeping in deep water. In: Proc. Offshore Technology Conference (OTC) 2000, Houston, TX, USA, May 2000. Paper No. 12087
Baarholm R, Fylling I, Stansberg C T, et al. Model testing of ultra-deepwater floater systems: truncation and software verification methodology. In: Proc. of 25th International Conference on Offshore Mechanics and Arctic Engineering, Hamburg, Germany, 2006. OMAE 2006-92492
Stansberg C T. On the fourier series decomposition of directional wave spectra. In: Proc. of the 8th International Offshore and Polar Engineering Conference, 1998. 227–234
Seung J L. The Effects of LNG-Sloshing on the Global Responses of LNG-Carriers. Dissertation for the Doctoral Degree. USA: Texax A&M University, 2008
Garrett D L. Dynamic analysis of slender rods. J Energy Resour Technol Trans ASME, 1982, 104: 302–307
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Zhao, W., Yang, J., Hu, Z. et al. Experimental and numerical investigation of the roll motion behavior of a floating liquefied natural gas system. Sci. China Phys. Mech. Astron. 56, 629–644 (2013). https://doi.org/10.1007/s11433-012-4914-3
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DOI: https://doi.org/10.1007/s11433-012-4914-3