Advancement of software in the loop system for current simulation in wave tanks

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dc.contributor.advisorMurphy, Jimmy
dc.contributor.advisorZabihi Kooykheily, Milad
dc.contributor.advisorEbrahimi Salari, Mahdi
dc.contributor.authorFrawley, Cillianen
dc.date.accessioned2025-05-13T10:45:48Z
dc.date.available2025-05-13T10:45:48Z
dc.date.issued2024
dc.date.submitted2024
dc.description.abstractModel testing in wave tanks is a valuable asset in the preliminary design phase of offshore floating wind turbines. Challenges arise when applying combined wind, wave and current loads in a single test location due to the differing scaling laws of air and water. Hybrid testing overcomes this issue by substituting one working fluid with a real-time numerical simulation using mechanical actuators. In hybrid testing in wave tanks, simulation of wind loads can be achieved using actuators such as cable winches or fans. Simulation of current loading is often overlooked. This thesis advances the Software-in-the-Loop (SIL) system for current simulation in wave tanks, building on the foundational work by Otter (2022). A comparison between tow testing and physical current testing to determine the hydrodynamic drag coefficient was conducted for both the 1/50 scale model of the INNWIND semi-submersible and the 1/30 scale model of the OE Buoy wave energy device. A broad scope of waves and current loads were tested to evaluate the SIL system for the INNWIND model. A winch actuator simulates current loading on a semi-submersible floating wind platform, through real-time simulations, applying drag forces derived from Morison’s equation. The winch actuation is determined by tension signals from a load cell, with motion-tracking cameras enabling dynamic adjustments based on platform velocity. Wave spectra are adjusted to account for wave-current interactions. Though a dual-winch system was planned to simulate various current angles, only single-winch actuation was achieved due to time and logistical constraints. The design of the control system and layout for the dual-winch are presented. Numerical simulations of the moored semi-submersible model in the Deep Ocean Basin (DOB) at the Lir National Ocean Test Facility (NOTF) were conducted in Ansys AQWA to validate the SIL system. The winch control accurately responded to the demanded drag force across tested environmental loads. For current-only tests, a coefficient of variation (CV) difference between demanded and measured tensions was less than 0.15, with this difference reducing at higher current velocities. Average demanded and measured tensions are within 0.5 % of each other for all velocities. For wave and current tests, the CV of the demanded tension increases significantly due to the wave load, however, the difference in CV between the demanded and measured tension remains less than 0.15 which signifies the Qualisys-SIL (QSIL) system’s ability to react dynamically to the environmental loads exerted on the platform in real-time.
dc.description.statusNot peer revieweden
dc.description.versionAccepted Versionen
dc.format.mimetypeapplication/pdfen
dc.identifier.citationFrawley, C. 2024. Advancement of software in the loop system for current simulation in wave tanks. MRes Thesis, University College Cork.
dc.identifier.endpage83
dc.identifier.urihttps://hdl.handle.net/10468/17471
dc.language.isoenen
dc.publisherUniversity College Corken
dc.rights© 2024, Cillian Frawley.
dc.rights.urihttps://creativecommons.org/licenses/by-nc-nd/4.0/
dc.subjectRenewables energy
dc.subjectFloating wind
dc.subjectTank testing
dc.subjectOffshore wind
dc.subjectNumerical modelling
dc.subjectControl engineering
dc.titleAdvancement of software in the loop system for current simulation in wave tanksen
dc.typeMasters thesis (Research)en
dc.type.qualificationlevelMastersen
dc.type.qualificationnameMRes - Master of Researchen
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