Unlike fossil fuels (e.g. oil, coal and natural gas), wind energy is a renewable energy resource. Since winds at sea are stronger and more consistent than onshore winds, the demand for offshore wind turbines has increased over the last years. As energy can be produced more efficient in deeper water, several floating offshore wind turbine constructions, such as the OC3 Hywind spar-buoy, have been proposed. The design of floating wind turbines depends on the simulation of the system behavior caused by exciting forces.
This thesis deals with the comparison between different methods for calculating wave forces and resulting platform motions of a floating offshore wind turbine. On the one hand, wave exciting loads computed with Morison’s equation are compared to the hydrodynamic forces simulated by the open source code FAST on the basis of the diffraction theory. On the other hand, response motions of the floating structure are simulated by the commercial offshore software SESAM in the frequency domain and compared with the motions calculated by FAST in the time domain.
Inhaltsverzeichnis (Table of Contents)
- Introduction
- Floating Offshore Wind Turbine Model
- OC3 Hywind
- OC3 Hywind System
- Calculation of Wave Loads
- Diffraction Theory (D/L > 0.2)
- Morison's Equation (D/L ≤ 0.2)
- Modified Morison's Equation
- Comparison of the Methods
- SESAM
- FAST
- Summary
- Conclusion and Outlook
Zielsetzung und Themenschwerpunkte (Objectives and Key Themes)
The main goal of this thesis is to present and compare different methods for calculating wave forces and resulting platform motions of a floating offshore wind turbine. The objective is to analyze the effectiveness and limitations of each method in simulating the dynamic behavior of a floating structure in a marine environment.
- Comparison of wave forcing and resulting platform motion calculation methods
- Analysis of wave loads on floating structures
- Floating offshore wind turbine design and modeling
- Evaluation of different numerical simulation tools
- Application of Morison's equation and diffraction theory
Zusammenfassung der Kapitel (Chapter Summaries)
- Introduction: This chapter provides background information on the increasing demand for offshore wind turbines and the development of floating substructures. It highlights the importance of simulating system behavior for designing floating wind turbines.
- Floating Offshore Wind Turbine Model: This chapter focuses on the OC3 Hywind model, a full-scale floating platform for offshore wind turbines. It details the Hywind spar-buoy design and its structural properties.
- Calculation of Wave Loads: This chapter explores different methods for calculating wave loads on floating structures. It covers diffraction theory, Morison's equation, and the modified Morison's equation, emphasizing the limitations and applicability of each method.
- Comparison of the Methods: This chapter presents a comparative analysis of different numerical simulation tools, including SESAM and FAST. It discusses their strengths and weaknesses in simulating wave forcing and platform motion.
Schlüsselwörter (Keywords)
This thesis focuses on floating offshore wind turbines, wave forcing, platform motion, numerical simulation, Morison's equation, diffraction theory, SESAM, FAST, Hywind spar-buoy, OC3, offshore renewable energy.
- Quote paper
- Olga Glöckner (Author), 2014, Comparison of methods for the computation of wave forcing, Munich, GRIN Verlag, https://www.grin.com/document/425814
