In this article, selecting an appropriate mooring system for the spar platform of a wind turbine consisting of chain–cable–chain is investigated based on a meta-heuristic method. A boundary element software is applied to hydrodynamics analysis, and the numerical results are verified by experimental results. According to the characteristics of the experimental mooring system, an appropriate chain is selected for the prototype model, and then a mooring system consisting of chain–cable–chain replaces the chain-based mooring system. Environmental forces have been applied by the conditions of the Caspian Sea. Analysis is done in time domain for irregular wave spectrum of Joint North Sea Wave Project. For the cable in the middle, seven lengths in the range of 30–210 m were considered. The simulations showed that in the cable length of 180 m, the structure exhibits a proper behavior. Also, in order to increase the reliability of the anchor, a portion of the initial chain was reduced and was added to the anchor chain; for this purpose, five different chain lengths from 25 to 65 m have been considered. The results show that for the heave, roll, pitch, and yaw degrees of freedom, the minimum structure oscillation happens in the length of 25 m, finally considering the proper behavior of the structure in the length of 25 m; this length of chain was added to the anchor chain.
AlamianRShafaghatRSafaeiMR. Multi-objective optimization of a pitch point absorber wave energy converter. Water2019; 11: 969.
2.
ZanousSPShafaghatRAlamianR, et al. Feasibility study of wave energy harvesting along the southern coast and islands of Iran. Renew Energy2019; 135: 502–514.
3.
EbrahimpourMShafaghatRAlamianR, et al. Numerical investigation of the Savonius vertical axis wind turbine and evaluation of the effect of the overlap parameter in both horizontal and vertical directions on its performance. Symmetry2019; 11: 821.
4.
JonkmanJM. Dynamics of offshore floating wind turbines—model development and verification. Wind Energy Int J Prog Appl Wind Power Convers Technol2009; 12: 459–492.
5.
NielsenFGHansonTDSkaareB. Integrated dynamic analysis of floating offshore wind turbines. In: 25th international conference on offshore mechanics and Arctic engineering, Hamburg, 4–9 June 2006, pp.671–679. New York: American Society of Mechanical Engineers.
6.
LassenTStorvollEBechA. Fatigue life prediction of mooring chains subjected to tension and out of plane bending. In: ASME 2009 28th international conference on ocean, offshore and Arctic engineering, Honolulu, HI, 31 May–5 June 2009, pp.229–239. New York: American Society of Mechanical Engineers.
7.
ZhangS-XTangY-GLiuH-X. Study on snap tension in mooring lines of deepwater platform. In: ASME 28th international conference on ocean, offshore and Arctic engineering, Honolulu, HI, 31 May–5 June 2009. New York: American Society of Mechanical Engineers.
8.
UtsunomiyaTSatoTMatsukumaH, et al. Experimental validation for motion of a spar-type floating offshore wind turbine using 1/22.5 scale model. In: ASME 28th international conference on ocean, offshore and Arctic engineering, Honolulu, HI, 31 May–5 June 2009, pp.951–959. New York: American Society of Mechanical Engineers.
BrommundtMKrauseLMerzK, et al. Mooring system optimization for floating wind turbines using frequency domain analysis. Energy Procedia2012; 24: 289–296.
11.
YuanZ-MIncecikAJiC. Numerical study on a hybrid mooring system with clump weights and buoys. Ocean Eng2014; 88: 1–11.
12.
MaYHuZ-QXiaoL-F. Wind-wave induced dynamic response analysis for motions and mooring loads of a spar-type offshore floating wind turbine. J Hydrodyn Ser B2015; 26: 865–874.
13.
ZhangDZhuKJingB, et al. Dynamic analysis of the mooring system for a floating offshore wind turbine spar platform. In: International conference on computer information systems and industrial applications, Bangkok, Thailand, 28–29 June 2015. Paris: Atlantis Press.
14.
AhmedMOYenduriAKurianV. Evaluation of the dynamic responses of truss spar platforms for various mooring configurations with damaged lines. Ocean Eng2016; 123: 411–421.
15.
TavakoliFShafaghatRAlamianR. Experimental study of the effect of gyroscope force on the stability of spar floating wind turbines. In: 18th international conference on offshore industries, Kish Island, Iran, 10–21 October 2016.
16.
EsmaeelpourKShafaghatRAlamianR, et al. Numerical study of various geometries of breakwaters for the installation of floating wind turbines. J Nav Archit Mar Eng2016; 13: 27–37.
17.
SamadiMHassanabadMG. Hydrodynamic response simulation of catenary mooring in the spar truss floating platform under Caspian Sea conditions. Ocean Eng2017; 137: 241–246.
18.
AzconaJMunduateXGonzálezL, et al. Experimental validation of a dynamic mooring lines code with tension and motion measurements of a submerged chain. Ocean Eng2017; 129: 415–427.
19.
BaeYKimMKimH. Performance changes of a floating offshore wind turbine with broken mooring line. Renew Energy2017; 101: 364–375.
20.
GhafariHDardelM. Parametric study of catenary mooring system on the dynamic response of the semi-submersible platform. Ocean Eng2018; 153: 319–332.
21.
LiuZTuYWangW, et al. Numerical analysis of a catenary mooring system attached by clump masses for improving the wave-resistance ability of a spar buoy-type floating offshore wind turbine. Appl Sci2019; 9: 1075.
22.
UllahZMuhammadNChoiD-H. Effect of hydrostatic nonlinearity on the large amplitude response of a spar type floating wind turbine. Ocean Eng2019; 172: 803–816.
23.
PhamH-DCartraudPSchoefsF, et al. Dynamic modeling of nylon mooring lines for a floating wind turbine. Appl Ocean Res2019; 87: 1–8.
24.
LiYLeCDingH, et al. Dynamic response for a submerged floating offshore wind turbine with different mooring configurations. J Mar Sci Eng2019; 7: 115.
25.
ChuangZLiuSLuY. Influence of second order wave excitation loads on coupled response of an offshore floating wind turbine. Int J Nav Archit Ocean Eng. Epub ahead of print 4February2020. DOI: 10.1016/j.ijnaoe.2020.01.003.
26.
ZhengXZhengHLeiY, et al. An offshore floating wind–solar–aquaculture system: concept design and extreme response in survival conditions. Energies2020; 13: 604.
27.
LianYYimSCZhengJ, et al. Effects of damaged fiber ropes on the performance of a hybrid taut-wire mooring system. J Offshore Mech Arct Eng2020; 142: 011607.
28.
GiorgiGGomesRPBraccoG, et al. The effect of mooring line parameters in inducing parametric resonance on the spar-buoy oscillating water column wave energy converter. J Mar Sci Eng2020; 8: 29
29.
National Renewable Energy Laboratory (NREL). Home page NREL, https://www.nrel.gov/ (accessed 22 February 2020).
30.
AlamianRShafaghatRHosseiniSS, et al. Wave energy potential along the southern coast of the Caspian Sea. Int J Mar Energy2017; 19: 221–234.
31.
HongSLeeIParkSH, et al. An experimental study of the effect of mooring systems on the dynamics of a SPAR buoy-type floating offshore wind turbine. Int J Nav Archit Ocean Eng2015; 7: 559–579.
32.
AlamianRShafaghatRBayaniR, et al. An experimental evaluation of the effects of sea depth, wave energy converter’s draft and position of centre of gravity on the performance of a point absorber wave energy converter. J Mar Eng Technol2017; 16: 70–83.
33.
KarimiradM. Stochastic dynamic response analysis of spar-type wind turbines with catenary or taut mooring systems. Doctoral Thesis, Norwegian University of Science and Technology, Trondheim, 2011.
34.
AlamianRShafaghatRShadlooMS, et al. An empirical evaluation of the sea depth effects for various wave characteristics on the performance of a point absorber wave energy converter. Ocean Eng2017; 137: 13–21.
35.
WichersJ. Guide to single point moorings. Houston, TX: WMooring, 2013.
36.
VeritasDN. Offshore standard DNV-OS-E301 position mooring. Høvik: Det Norske Veritas, 2010.
37.
TafazzoliSShafaghatR. Investigating the behavior of the mooring system for a conceptual design of a spar floating wind turbine under survival conditions. J Mar Eng2019; 15: 49–62.
38.
NewmanJN. The theory of ship motions. New York: Academic Press, 1978.
39.
HavelockTH. Waves due to a floating sphere making periodic heaving oscillations. Proc Roy Soc Lond Ser A Math Phys Sci1955; 231: 1–7
40.
HessJLSmithAMO. Calculation of potential flow about arbitrary bodies. Prog Aerosp Sci1967; 8: 1–138.
GhafariHRKetabdariMJGhassemiH, et al. Numerical study on the hydrodynamic interaction between two floating platforms in Caspian Sea environmental conditions. Ocean Eng2019; 188: 106273.
