Guodong Liang

• Liang, Guodong; Wickmann Hanssen, Finn-Christian; Otto Merz, Karl & Jiang, Zhiyu (2024). Numerical analysis of a tethered-buoy mooring system for a prototype floating wind farm. Wind Energy. ISSN 1095-4244. 27(5), p. 500–529. doi: 10.1002/we.2898.
• Liang, Guodong; Lopez-Olocco, Tomas; Medina-Manuel, Antonio; Saavedra-Ynocente, Leandro Antonio; Souto-Iglesias, Antonio & Jiang, Zhiyu (2024). Experimental investigation of two shared mooring configurations for a dual-spar floating offshore wind farm in irregular waves. Marine Structures. ISSN 0951-8339. 95. doi: 10.1016/j.marstruc.2024.103579. Full text in Research Archive
• Lopez-Olocco, Tomas; Liang, Guodong; Medina-Manuel, Antonio; Ynocente, Leandro Saavedra; Jiang, Zhiyu & Souto-Iglesias, Antonio (2023). Experimental comparison of a dual-spar floating wind farm with shared mooring against a single floating wind turbine under wave conditions. Engineering structures. ISSN 0141-0296. 292. doi: 10.1016/j.engstruct.2023.116475. Full text in Research Archive Show summary

  Shared mooring can potentially be a cost-reduction factor for future floating wind farms. To assess the effect of shared mooring on the response dynamics of floating wind turbines (FWTs), experiments have been conducted for two spar FWTs with a shared mooring configuration and for a single spar FWT with catenary mooring, both at a scale of 1:47. Various regular and irregular wave conditions were tested and only one wave heading was considered. From the test results, the response amplitude operators and response spectra of platform motions and statistics of mooring tensions are compared for the two configurations. In the extreme wave condition, the shared mooring configuration leads to a 40% increase in the platform surge motion compared with the single spar FWT. Still, the absolute offset is within allowable limits prescribed by power cables. The fairlead tensions of the anchor lines are not significantly increased in the shared mooring configurations, but the shared line shows extreme tension peak events that are seldom present in the anchor lines. This study demonstrates the technological promises and challenges of a shared mooring system from an experimental perspective. Results and videos are made available and can be used to validate numerical models.

• Liang, Guodong; Jiang, Zhiyu & Merz, Karl Otto (2023). Dynamic analysis of a dual-spar floating offshore wind farm with shared moorings in extreme environmental conditions. Marine Structures. ISSN 0951-8339. 90. doi: 10.1016/j.marstruc.2023.103441. Full text in Research Archive Show summary

  The concept of a shared mooring system was proposed to reduce mooring and anchoring costs. Shared moorings also add complexity to the floating offshore wind farm system and pose design challenges. To understand the system dynamics, this paper presents a dynamic analysis for a dual-spar floating offshore wind farm with a shared mooring system in extreme environmental conditions. First, a numerical model of the floating offshore wind farm was established in a commercial simulation tool. Then, time-domain simulations were performed for the parked wind farm under extreme wind and wave conditions. A sensitivity study was carried out to investigate the influence of loading directions and shared line mooring properties. To highlight the influence of the shared line, the results were compared to those of a single spar floating wind turbine, and larger platform motions and higher tension loads in single lines are observed for the wind farm with shared moorings. The loading direction affects the platform motions and mooring response of the floating offshore wind farm. Comparing the investigated loading directions to the 0-deg loading direction, the variation of mean mooring tension at the fairlead is up to 84% for single lines and 16% for the shared line. The influence of the shared line properties in the platform motions and the structural responses is limited. These findings improve understanding of the dynamic characteristics of floating offshore wind farms with a shared mooring system.

• Jiang, Zhiyu; Liang, Guodong; Lopez-Olocco, Tomas; Medina-Manuel, Antonio; Saavedra-Ynocente, L.A. & Souto-Iglesias, Antonio (2023). Model test of a dual-spar floating wind farm in regular waves. In Ringsberg, J. W. & Soares, C. Guedes (Ed.), Advances in the analysis and design of marine structures : Proceedings of the 9th International Conference on Marine Structures (MARSTRUCT 2023), Gothenburg, Sweden, 3-5 April 2023 . CRC Press. ISSN 9781003399759. Full text in Research Archive Show summary

  A floating wind farm with shared moorings has the potential to reduce capital expenditure but may face structural dynamics issues. We selected a prototype wind farm that consists of two spar floating wind turbines with shared moorings and carried out model tests with a scale factor of 1:47. Rigid-body motions of one spar and mooring line tensions were measured. In this paper, the test setup is described, and results from the decay and regular-wave tests are discussed. In regular waves, the spar motions in surge, heave, and pitch are dominated by wave frequencies and the extreme motion ranges are acceptable. Compared with the baseline, the clump weight affects the mean position of platform motion; it also reduces the dynamic tension of the shared line but causes higher mean and maximum tension in the single lines. This paper contributes to an improved understanding of complex floating systems in offshore environments.

• Liang, Guodong; Jiang, Zhiyu & Merz, Karl Otto (2022). Influence of Aerodynamic Loads on a Dual-Spar Floating Offshore Wind Farm With a Shared Line in Parked Conditions. In 41st OMAE, 2022 (Eds.), ASME 2022 41st International Conference on Ocean, Offshore and Arctic Engineering Volume 8: Ocean Renewable Energy. The American Society of Mechanical Engineers (ASME). ISSN 978-0-7918-8593-2. doi: 10.1115/OMAE2022-78929. Full text in Research Archive Show summary

  The concept of a shared mooring system, in which adjacent wind turbines are coupled by sharing mooring lines, has been proposed to reduce the mooring costs of floating offshore wind farms. This work investigates the influence of aerodynamic loads on a floating offshore wind farm of two spar wind turbines connected with a shared line in extreme environmental conditions. A case study is performed for the floating offshore wind farm under parked conditions using a numerical simulation tool. The environmental conditions are determined from environmental contours with a return period of 50 years. Turbulent wind and irregular waves are simulated in dynamic analyses. Wind and waves are aligned and two loading directions are considered. Floater motions and structural response are analyzed. The influence of aerodynamic loads is studied by comparing the simulation results under both wind and waves with those under wave-only. It is concluded that the aerodynamic loads affect the horizontal motions of floating offshore wind turbines, the mooring response and the tower-base bending moment significantly in extreme environmental conditions, especially when the loading direction is 90 deg. The findings from this study improve understanding of the design loads of shared mooring systems.

• Liang, Guodong; Jiang, Zhiyu & Merz, Karl Otto (2021). Mooring Analysis of a Dual-Spar Floating Wind Farm With a Shared Line. Journal of Offshore Mechanics and Arctic Engineering. ISSN 0892-7219. 143(6). doi: 10.1115/1.4050965. Full text in Research Archive
• Liang, Guodong; Merz, Karl Otto & Jiang, Zhiyu (2020). Modeling of a Shared Mooring System for a Dual-Spar Configuration, ASME 2020 39th International Conference on Ocean, Offshore and Arctic Engineering - Volume 9: Ocean Renewable Energy. The American Society of Mechanical Engineers (ASME). ISSN 978-0-7918-8441-6. doi: 10.1115/OMAE2020-18467. Full text in Research Archive

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• Liang, Guodong (2023). Numerical and Experimental Study of Shared Mooring Systems for Prototype Floating Wind Farms. Universitetet i Agder. ISSN 1504-9272. Full text in Research Archive

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