City Research Online

Abstract

Hybrid systems integrating offshore wind turbines (OWTs) and wave energy converters (WECs) can significantly reduce overall costs and enhance spatial utilization of marine areas. This paper presents wave basin experiments for two hybrid systems—the monopile segmented-buoy combination system (MSCS) and the monopile torus-buoy combination system (MTCS)—to comparatively study the hydrodynamic response and power performance under both regular and irregular wave conditions. The 1:25 Froude similarity scaled model of the MSCS can transform to an MTCS by connecting the three buoys with extra connectors and filling their gaps with foam boards. A hydraulic PTO system is adopted for wave energy conversion. In addition to employing the Response Amplitude Operator (RAO) to analyze buoy motion characteristics, a novel parameter, i.e., Response Cycle Ratio (RCR), is proposed to quantitatively assess wave-following behavior, particularly under irregular wave conditions. The results show that RAO peaks consistently occur near the buoy' natural periods, with motion amplitudes gradually decreasing relative to wave amplitudes as wave periods increase, while the RCR progressively rises. Under the same wave periods and wave energy flux, the MSCS system exhibits higher power capture in regular waves compared to irregular waves, while both conditions share comparable optimal Coulomb PTO forces. Moreover, the MSCS system outperformed the MTCS system in energy capture, particularly in shorter-period waves, but both systems maintained nearly identical optimal PTO. This research provides valuable guidance for designing and optimizing hybrid systems incorporating heaving-type buoys, while also supplying reliable experimental data for numerical model validation.

Publication Type:	Article
Additional Information:	© 2025 Elsevier Ltd. All rights are reserved, including those for text and data mining, AI training, and similar technologies. This manuscript version is made available under the CC-BY-NC-ND 4.0 license https://creativecommons.org/licenses/by-nc-nd/4.0/
Publisher Keywords:	Wave energy converter, Hybrid wind-wave system, Comparative experimental study, Hydrodynamic characteristics, Irregular waves
Subjects:	T Technology > TA Engineering (General). Civil engineering (General) V Naval Science > VM Naval architecture. Shipbuilding. Marine engineering
Departments:	School of Science & Technology School of Science & Technology > Department of Engineering
SWORD Depositor:	Symplectic Administrator

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