Dynamic analysis of offshore triceratops supporting wind turbine: Preliminary studies
Keywords:Triceratops, Wind turbine, Fatigue life, Hydrodynamic, Aerodynamic, Partial isolation, Dynamic analysis
Offshore triceratops, the recent innovation in deep water compliant platforms, is primarily designed to withstand lateral forces through its geometric shape. The uniqueness of the platform is the presence of the ball joints between the legs and deck, which partially restrain the transfer of rotations from the legs to the deck and vice-versa. However, displacements such as surge, sway, and heave motions are transferred, ensuring a rigid connection between the legs and the deck. Efficient operations of offshore wind turbines are more dependent on the support systems on which they are mounted. Increased stability and reduction in stress concentration in rigid connections are desirable. Nonlinear dynamic response analysis is carried out in FAST by coupling the frequency response of the platform obtained in ANSYS AQWA with that of the HydroDyn module of FAST. The current study investigates a fully coupled three-dimensional hydro-aerodynamic model of triceratops mounted with a horizontal axis wind turbine. Unsteady Blade Element Momentum theory (BEM) is used to estimate the aerodynamic loads, which encompasses the effect of wind shear using a power law and spatially coherent turbulence. In contrast, Morison equations are used to estimate the hydrodynamic loads on the platform. After the preliminary proportioning of the platform, Response Amplitude Operator (RAO) plots are drawn to illustrate the partial motion transfer between the deck and the buoyant legs. Based on the preliminary studies, it is seen that the environmental loads do not impose instability, reinforcing the dynamic stability of the platform. Frequency responses for operating and parked conditions illustrate the coupling between the degrees of freedom and the influence of the rotor motion of the wind turbine on the platform deck. Tether tension variation is assessed in all three legs for the operational sea states to check the safety standards for a compliant system to avoid tether pull-out. The presented study is prima facie to encourage the suitability of triceratops as floaters to support the wind turbine under moderate sea states.
- This study is focused on new-generation offshore triceratops as support system for wind turbine
- Prelimiary dynamic anlaysis of coupled action of the supprting system and wind turbine are presented
- Use of ball joints help partial isolation of the deck and restrain transfer of moment from the turbine shaft to the supporting system, which is a novelty
- Infleunce of rotor motion of the triceratops is illustarted to highlight the advantage of complinacy of trirceratops
- This study disucsses only the performance assessment and not the design perspectives
Butterfield, S., Musial, W., Jonkman, J., Sclavounos, P., & Wayman, L. (2005). Engineering challenges for floating offshore wind turbines. In Proceedings of the Copenhagen Offshore Wind Conference and Expedition. Copenhagen, Denmark.
Chandrasekaran, S., & Chauhan, B. S. Y. (2022). Dynamic analyses of Triceratops under Hurricane-drive Metocean conditions in Gulf of Mexico. Ocean Engineering, 256, 111511. https://doi.org/10.1016/j.oceaneng.2022.111511
Chandrasekaran, S., Shah, B., & Chauhan, Y. J. (2023a). Fatigue assessment of offshore triceratops restraining system under Hurricane-driven Metocean conditions. International Journal of Steel Structures, 23, 208-224. https://doi.org/10.1007/s13296-022-00689-w
Chandrasekaran, S., Shah, B., & Chauhan, Y. J. (2023b). Tether response of offshore Triceratops under hurricane conditions. Structures, 51, 513-527. https://doi.org/10.1016/j.istruc.2023.03.059
Fulton, G. R., Malcolm, D. J., & Moroz, E. (2006). Design of a semi-submersible platform for a 5MW wind turbine. In Proceedings of the 44th Aerospace Sciences Meeting and Exhibit. Reno. https://doi.org/10.2514/6.2006-997
Henderson, A. R., & Morgan, C. S. (2003). Offshore wind energy in Europe: A review of the state of Art. Wind Energy, 6(1), 35-52. https://doi.org/10.1002/we.82
Henderson, A. R., & Patel, M. H. (2003). On the modelling of a floating offshore wind turbine. Wind Energy, 6(1), 53-86. https://doi.org/10.1002/we.83
Jonkman, J. M. (2003). Modeling of the UAE wind turbine for refinement of FAST_AD (pp. pp. 1-177). Technical Report, National Renewable Energy Laboratory, Colorado. https://doi.org/10.2172/15005920
Jonkman, J. M., & Buhl, M. L. Jr. (2007). Loads analysis of a floating offshore wind turbine using fully-coupled simulation (pp. 1-32). In Proceedings of the Wind power 2007 Conference. Los Angeles, California.
Kai-Tung, M., Luo, Y., Kwan, T., & Wu, Y. (2019). Fatigue analysis. Mooring System Engineering for Offshore Structures (pp. 115-137). Gulf Professional Publishing. https://doi.org/10.1016/B978-0-12-818551-3.00006-5
Larsen, T. J., & Hanson, T. D. (2007). A method to avoid negative damped low-frequent tower vibrations for a Floating, pitch-controlled Wind Turbine. In Proceedings of the 2nd Conference Science of Making Torque from Wind. Copenhagen, Denmark. https://doi.org/10.1088/1742-6596/75/1/012073
Matha, D., Fischer, T., Kuhn, M., & Jonkman, J. (2010). Model development and load analysis of a floating offshore tension leg platform. In Proceedings of the National Renewable Energy Laboratory. Stockholm, Sweden. https://doi.org/10.2172/972932
Musial, W., & Butterfield, S. (2004). Future of offshore wind energy in the United States. In Proceedings of the Energy Ocean. Palm Beach, Florida.
Musial, W., Butterfield, S., & Boone, A. (2004). Feasibility of floating platform systems for wind turbines. In Proceedings of the ASME Wind Energy System. New York. https://doi.org/10.2514/6.2004-1007
Musial, W., Butterfield, S., & Ram, B. (2006). Energy from offshore wind. In Proceedings of the Offshore Technology. Conference. Houston, Texas. https://doi.org/10.4043/18355-MS
Nielsen, F. G., Hanson, T. D., & Skaare, B. (2006). Integrated dynamic analysis of floating offshore wind turbines. In Proceedings of the 25th International Conference on Offshore Mechanics and Arctic Engineering. Hamburg, Germany. https://doi.org/10.1115/OMAE2006-92291
Skaare, B., Hanson, T. D., & Nielsen, F. G. (2007). Importance of control strategies on fatigue life of floating wind turbines. In Proceedings of the 26th International Conference on Offshore Mechanics and Arctic Engineering. San Diego. https://doi.org/10.1115/OMAE2007-29277
Srinivasan, C. (2014). Advanced theory on offshore plant FEED engineering (pp. 1-237). Changwon National University Press, Republic of South Korea.
Srinivasan, C. (2015). Advanced marine structures. CRC Press, Florida.
Srinivasan, C. (2016). Offshore structural engineering: Reliability and risk assessment. CRC Press, Florida.
Srinivasan, C. (2017). Dynamic analysis and design of ocean structures. 2nd eds. Springer, Singapore.
Srinivasan, C. (2020). Offshore semi-submersible platform engineering (pp. 1-240). CRC Press, Florida.
Srinivasan, C., & Faisal, K. R. A. (2022). Wave energy devices: Design, Development and Experimental studies (pp. 1-271). CRC Press, Florida.
Srinivasan, C., & Jain, A. K. (2016). Ocean structures: Construction, materials and operations. CRC Press, Florida.
Srinivasan, C., & Madhuri, S. (2012). Stability studies of offshore triceratops. International Journal of Research and Development, 1(10), 398-404.
Srinivasan, C., & Madhuri, S. (2015). Dynamic response of offshore triceratops: Numerical and Experimental investigations. Ocean Engineering, 109(15), 401-409. https://doi.org/10.1016/j.oceaneng.2015.09.042
Srinivasan, C., & Nagavinothini, R. (2020). Offshore compliant platforms: Analysis, design and experimental studies. Wiley, U.K.
Srinivasan, C., & Seeram, M. (2012a). Free vibration response of offshore triceratops: Experimental and analytical investigations (pp. 965-968). In Proceedings of the 3rd Asian Conference on Mechanics of Functional Materials and Structures. IIT Delhi, India.
Srinivasan, C., & Seeram, M. (2012b). Stability studies on offshore triceratops (pp. 398-404). In Proceedings of the Tech Samudhra International Conference on Technology of the Sea. Indian Maritime University, Vishakapatnam.
Srinivasan, C., & Senger, M. (2017). Dynamic analyses of stiffened triceratops under regular waves: Experimental investigations. Ships and Offshore Structures, 12(5), 697-705. https://doi.org/10.1080/17445302.2016.1200957
Srinivasan, C., & Subrata, K. B. (2012). Analysis and design of offshore structures with illustrated examples (pp. 1-285). Human Resource Development Center for Offshore and Plant Engineering (HOPE Center), Changwon National University Press, Republic of Korea.
Srinivasan, C., Jain, A. K., & Seeram, M. (2013). Aerodynamic response of offshore triceratops. Ships, and Offshore Structures, 8(2), 123-140. https://doi.org/10.1080/17445302.2012.691271
Srinivasan, C., Madhuri, N. (2013). Response analyses of offshore triceratops to seismic activities. Ship and Offshore Structures, 9(6), 633-642. https://doi.org/10.1080/17445302.2013.843816
Srinivasan, C., Mayank, S., & Jain, A. (2015). Dynamic response behavior of stiffened triceratops under regular waves: Experimental investigations. In Proceedings of the 34th International Conference on Ocean, Offshore and Arctic Engineering. St. John's, NL, Canada.
Srinivasan, C., Seeram, M., Jain, A. K., & Gaurav. (2010). Dynamic response of offshore triceratops under environmental loads (pp. 61-66). In Proceedings of the International Conference on Marine Technology. Dhaka, Bangladesh.
Srinivasan, C., Sundaravadivelu, R., Pannerselvam, R., & Madhuri, S. (2011). Experimental investigations of offshore triceratops under regular waves. In Proceedings of the 30th International Conference on Ocean, Offshore and Arctic Engineering. Rotterdam, The Netherlands.
Wayman, E. N., Sclavounos, P. D., Butterfield, S., Jonkman, J., & Musial, W. (2006). Coupled dynamic modeling of floating wind turbine systems. In Proceedings of the Offshore Technology Conference. Houston, Texas. https://doi.org/10.4043/18287-MS
Zambrano, T., MacCready, T., Kiceniuk, T., Roddier, D. G., & Cermelli, C. A. (2006). Dynamic modeling of deepwater offshore wind turbine structures in Gulf of Mexico Storm Conditions. In Proceedings of the 25th International Conference on Offshore Mechanics and Arctic Engineering. Hamburg, Germany. https://doi.org/10.1115/OMAE2006-92029
Zambrano, T., MacCready, T., Roddier, D. G., & Cermelli, C.A. (2007). Design and installation of a tension moored wind turbine. In Proceedings of the 26th International Conference on Offshore Mechanics and Arctic Engineering. San Diego. https://doi.org/10.1115/OMAE2007-29587
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