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Efficient modeling of floating offshore wind turbines

PhD defence, Wednesday 8 February, 2023, Christian Elkjær Høeg

Christian Elkjær Høeg

During his PhD studies Christian Elkjær Høeg researched the modeling of floating offshore wind turbines (FOWTs) within the modal-based modeling framework. It is estimated, that 80% of the worlds wind resources has water depths beyond 60 meters, where FOWTs become more economical than bottom fixed offshore wind turbines. FOWTs precents new modeling challenges compared to bottom fixed offshore wind turbines due to complex hydrodynamics and a mooring system for station keeping. Christian Elkjær Høeg studied the application of structural dynamic modeling through the Euler-Lagrange method to FOWTs and expanded on the reaction loads extraction, hydrodynamics and proposed a novel damper.

The new research findings contribute to the understanding of fundamental structural dynamics of the complex FOWT system and the couplings between the components through explicit equations of motion. Furthermore, a novel semi-analytic hydrodynamic model is proposed as well as a novel damper for suppression of both tower and foundation vibrations.

The PhD study was completed at the Department of Civil and Architectural Engineering, Faculty of Technical Sciences, Aarhus University.

This summary was prepared by the PhD student.

Time: Wednesday, February 8th, 2022, at 13:00
Place: Building 3210, room 0.117, "Auditoriet", Department of Civil and Architectural Engineering, Aarhus University, Inge Lehmanns Gade 10, Navitas, 8000 Aarhus

Title of PhD thesis: Efficient time-domain modeling, load evaluation and control of floating offshore wind turbines

Contact information: Christian Elkjær Høeg, e-mail: chr.hoeeg@gmail.com, tel.: +45 29803851

Members of the assessment committee:

Professor Henrik Bredmose, Department of Wind and Energy Systems, Technical University of Denmark

Professor Zhen Gao, Department of Marine Technology, Norwegian University of Science and Technology, Norway

Associate Professor Min Wu (chair), Department of Civil and Architectural Engineering, Aarhus University, Denmark

Main supervisor:
Professor Lars Vabbersgaard Andersen, Department of Civil and Architectural Engineering, Aarhus University, Denmark

Co-supervisor:
Professor Zili Zhang, Department of Architectural Engineering, Tongji University, China

Language: The PhD dissertation will be defended in English

The defence is public.
The PhD thesis is available for reading at the Graduate School of Technical Sciences/GSTS,

Jens Baggesens Vej 53, building 5221, 8200 Aarhus N.

17427 / i43