Numerical Investigation of Heave and Pitch Motion Effects on Green Water Loading for a Floating Body

Abstract

In this paper, the influence of heave and pitch motions on green water impact on the deck is numerically investigated. The vessel motions are determined using a potential theory based method and provided as input to finite volume based CFD computations of green water phenomenon. A dynamic mesh approach is adopted to determine instantaneous body positioning in the fluid domain. Detailed validation studies with published experimental results for 2D and 3D fixed vessel cases are initially performed to validate the present numerical approach before studying the moving vessel problem. The results show that inclusion of heave and pitch motion changes the disturbed wave field near the bow which influences the free surface as well as the impact loading due to green water. The effect of wave steepness on green water impact is also investigated and it is seen that the present numerical method is capable of capturing green water load. It is observed that the effects of vessel motions on green water load are not negligible and one should consider this effect too. The incorporation of vessel motions in the vertical plane affects the green water loading on the deck.

Keywords

Green water impact pressure / Relative wave height / Vertical bow motion / Heave and pitch motions / Wave steepness / Floating body

References

[1] Buchner B (1995) The impact of green water on FPSO design. Offshore Technology Conference, Houston, USA

[2] Buchner B, Cozijn JL (1997) An investigation into the numerical simulation of green water. Proc. Int. Conf. on the Behavior of Offshore Structures, BOSS’97, vol 2, 113–125

[3] Buchner B, Voogt A (2000) The effect of bow flare angle on FPSO green water loading. Proceedings of ETCE/OMAE2000 Joint Conference Energy for the New Millenium, New Orleans

[4] Datta R, Fonseca N. Analysis of the forward speed effects on the radiation forces on a fast ferry. Ocean Eng, 2013, 60: 136-148

[5] Datta R, Rodrigues JM, Guedes Soares C. Study of the motions of fishing vessels by a time domain panel method. Ocean Eng, 2011, 38(5): 782-792

[6] De Carvalhoe Silva DF, Rossi RR (2014) Green water loads determination for FPSO exposed to beam sea conditions. 33rd International Conference on Ocean, Offshore and Arctic Engineering, V08BT06A012-V08BT06A012. San Fransisco

[7] Faltinsen OM, Greco M, Landrini M. Green water loading on a FPSO. J Offshore Mech Arct Eng, 2002, 124(2): 97-103

[8] Gorf P, Barltrop N, Okan B, Hodgson T, Rainey R (2000) FPSO bow damage in steep waves. Rogue Waves 2000 Workshop, Brest, vol 32, 37

[9] Greco M. A two-dimensional study of green-water loading. PhD, 2001, Trondheim: Norwegian University of Science and Technology

[10] Greco M, Lugni C. 3-D seakeeping analysis with water on deck and slamming. Part 1: numerical solver. J Fluids Struct, 2012, 33: 127-147

[11] Greco M, Landrini M, Faltinsen OM. Impact flows and loads on ship-deck structures. J Fluids Struct, 2004, 19(3): 251-275

[12] Greco M, Bouscasse B, Lugni C. 3-D seakeeping analysis with water on deck and slamming. Part 2: experiments and physical investigation. J Fluids Struct, 2012, 33: 148-179

[13] Greco M, Colicchio G, Lugni C, Faltinsen OM. 3D domain decomposition for violent wave-ship interactions. Int J Numer Methods Eng, 2013, 95(8): 661-684

[14] Greco M, Lugni C, Faltinsen OM. Can the water on deck influence the parametric roll of a FPSO? A numerical and experimental investigation. Eur J Mech, 2014, 47: 188-201 B/Fluids

[15] Greco M, Lugni C, Faltinsen OM. Influence of motion coupling and nonlinear effects on parametric roll for a floating production storage and offloading platform. Phil Trans R Soc A, 2015, 373(2033): 20140110

[16] Hirt CW, Nichols BD. Volume of fluid (VOF) method for the dynamics of free boundaries. J Comput Phys, 1981, 39(1): 201-225

[17] Kleefsman KT, Loots GE, Veldman AE, Buchner B, Bunnik T, Falkenberg E (2005) The numerical simulation of green water loading including vessel motions and the incoming wave field. 24th International Conference on Offshore Mechanics and Arctic Engineering, Halkidiki, Greece, 981–992

[18] Le Touze D, Marsh A, Oger G, Guilcher PM, Khaddaj-Mallat C, Alessandrini B, Ferrant P. SPH simulation of green water and ship flooding scenarios. J Hydrodyn Ser B, 2010, 22(5): 231-236

[19] Lee YG, Kim N, Kang BH, Jeong KL. Numerical simulation of green water incident on bow deck. The Nineteenth International Offshore and Polar Engineering Conference, 2009, Osaka: International Society of Offshore and Polar Engineers, 495-502

[20] Lee HH, Lim HJ, Rhee SH. Experimental investigation of green water on deck for a CFD validation database. Ocean Eng, 2012, 42: 47-60

[21] Lu H, Yang C, Löhner R. Numerical studies of green water impact on fixed and moving bodies. Int J Offshore Polar Eng, 2012, 22(2): 123-132

[22] Nielsen KB, Mayer S. Numerical prediction of green water incidents. Ocean Eng, 2004, 31(3): 363-399

[23] Park JC, Kim MH, Miyata H. Fully non-linear free-surface simulations by a 3D viscous numerical wave tank. Int J Numer Methods Fluids, 1999, 29(6): 685-703

[24] Sengupta D, Datta R, Sen D. A simplified approach for computation of nonlinear ship loads and motions using a 3D time-domain panel method. Ocean Eng, 2016, 117: 99-113

[25] Shibata K, Koshizuka S. Numerical analysis of shipping water impact on a deck using a particle method. Ocean Eng, 2007, 34(3): 585-593

[26] Tanizawa K, Sawada H, Tsujimoto M, Koshizuka S (2004). Experimental and numerical study of shipping water impact on running ship foredeck in regular head seas. Hydrodynamics VI: Theory and Applications: Proceedings of the 6th International Conference on Hydrodynamics, Perth, Western Australia, 125

[27] Theilen L, Detlefsen O, Abdel-Maksoud M, Bohm M (2015) Efficient simulation method to predict green water loads on superstructures. 34th International Conference on Ocean Offshore and Arctic Engineering. Newfoundland, Canada, V001T01A035-V001T01A035

[28] Voogt A, Buchner B (2004) Prediction of wave impact loads on ship-type offshore structures in steep fronted waves. The Fourteenth International Offshore and Polar Engineering Conference. Toulon, France, ISOPE-I-04-063

[29] Voogt AJ, Buchner B, Garcia JLC (2004) Wave impact excitation on ship-type offshore structures in steep fronted waves. Proceedings OMAE Speciality Conference on Integrity of Floating Production, Storage & Offloading (FPSO) Systems, Houston, 04-0062

[30] Zhao X, Ye Z, Fu Y. Green water loading on a floating structure with degree of freedom effects. J Mar Sci Technol, 2014, 19(3): 302-313

[31] Zhu R, Miao G, Lin Z. Numerical research on FPSOs with green water occurrence. J Ship Res, 2009, 53(1): 7-18

[32] Zwart PJ, Godin PG, Penrose J, Rhee SH (2007). Ship hull simulations with a coupled solution algorithm. Proceedings of the 10th International Symposium on Practical Designs of Ships and Other Floating Structures, Houston