Wind Energy Methods For Computation Of Wave Forcing And The Resulting Motion Of A Slender Offshore Floating Structure PDF Download
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| Author | : Olga Glöckner |
| Publisher | : GRIN Verlag |
| Total Pages | : 151 |
| Release | : 2018-07-19 |
| Genre | : Technology & Engineering |
| ISBN | : 3668754780 |
Download Wind energy. Methods for computation of wave forcing and the resulting motion of a slender offshore floating structure Book in PDF, ePub and Kindle
Academic Paper from the year 2014 in the subject Engineering - Civil Engineering, grade: 1,0, University of Hannover (A&M University Texas, Ludwig-Franzius-Institut für Wasserbau, Ästuar- und Küsteningenieurwesen), language: English, abstract: This thesis investigates how wave loads act on an OC3 Hywind spar-buoy. The author analyzes the resulting motions of the support platform. This work also contains a detailed presentation of the topic with useful additional information and graphics. Unlike fossil fuels (like 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. A general overview of regular and irregular waves as well as hydrostatic and hydrodynamic loads acting on floating structures is given in chapter 2. Furthermore, essential formulations for calculating motions of FOWTs are given at the end of this chapter. Since all simulations carried out in this thesis are based on the OC3 Hywind concept, detailed information about this floating wind turbine model are given in chapter 3. Three different methods are used for the estimation of wave induced loads and motions. Section 4 describes a modified Morison formulation in the time domain which is applied by the commercially available software MATLAB. On the basis of the diffraction theory the commercial offshore software package SESAM simulates wave excitation forces and responding motions which are presented and discussed in chapter 5. The third method is the open source code FAST that computes wave induced loads and motions based on the first-order potential theory and Kane’s equation of motion. Basic formulations used in FAST and essential hydrodynamic results are shown in chapter 6. The comparisons between the simulations of the three programs are represented and the individual results are analyzed in chapter 7.
| Author | : Olga Glöckner |
| Publisher | : GRIN Verlag |
| Total Pages | : 14 |
| Release | : 2018-05-18 |
| Genre | : Technology & Engineering |
| ISBN | : 366870614X |
Download Comparison of methods for the computation of wave forcing Book in PDF, ePub and Kindle
Presentation slides from the year 2014 in the subject Engineering - Civil Engineering, grade: 1,0, University of Hannover, language: English, abstract: 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.
| Author | : Olga Glöckner |
| Publisher | : GRIN Verlag |
| Total Pages | : 137 |
| Release | : 2018-05-17 |
| Genre | : Technology & Engineering |
| ISBN | : 3668705224 |
Download A comparison of methods for computation of wave forcing Book in PDF, ePub and Kindle
Diploma Thesis from the year 2014 in the subject Engineering - Civil Engineering, grade: 1,0, University of Hannover (A&M University Texas, Ludwig-Franzius-Institut für Wasserbau, Ästuar- und Küsteningenieurwesen), language: English, abstract: Unlike fossil fuels (for example 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.
| Author | : |
| Publisher | : |
| Total Pages | : 65 |
| Release | : 2015 |
| Genre | : |
| ISBN | : |
Download Wave Loads on Offshore Wind Turbines Book in PDF, ePub and Kindle
Ocean energy is one of the most important sources of alternative energy and offshore floating wind turbines are considered viable and economical means of harnessing ocean energy. The accurate prediction of nonlinear hydrodynamic wave loads and the resulting nonlinear motion and tether tension is of crucial importance in the design of floating wind turbines. A new theoretical framework is presented for analyzing hydrodynamic forces on floating bodies which is potentially applicable in a wide range of problems in ocean engineering. The total fluid force acting on a floating body is obtained by the time rate of change of the impulse of the velocity potential flow around the body. This new model called Fluid Impulse Theory is used to address the nonlinear hydrodynamic wave loads and the resulting nonlinear responses of floating wind turbine for various wave conditions in a highly efficient and robust manner in time domain. A three-dimensional time domain hydrodynamic wave-body interaction computational solver is developed in the frame work of a boundary element method based on the transient free-surface Green-function. By applying a numerical treatment that takes the free-surface boundary conditions linearized at the incident wave surface and takes the body boundary condition satisfied on the instantaneous underwater surface of the moving body, it simulates a potential flow in conjunction with the Fluid Impulse Theory for nonlinear wave-body interaction problems of large amplitude waves and motions in time domain. Several results are presented from the application of the Fluid Impulse Theory to the extreme and fatigue wave load model: the time domain analysis of nonlinear dynamic response of floating wind turbine for extreme wave events and the time domain analysis of nonlinear wave load for an irregular sea state followed by a power spectral density analysis.
| Author | : Enzo Marino |
| Publisher | : Firenze University Press |
| Total Pages | : 232 |
| Release | : 2010 |
| Genre | : Coastal engineering |
| ISBN | : 8866550515 |
Download An Integrated Nonlinear Wind-Waves Model for Offshore Wind Turbines Book in PDF, ePub and Kindle
This thesis presents a numerical model capable of simulating offshore wind turbines exposed to extreme loading conditions. External condition-based extreme responses are reproduced by coupling a fully nonlinear wave kinematic solver with a hydro-aero-elastic simulator. First, a two-dimensional fully nonlinear wave simulator is developed. The transient nonlinear free surface problem is formulated assuming the potential theory and a high-order boundary element method is implemented to discretize Laplace's equation. For temporal evolution a second-order Taylor series expansion is used. The code, after validation with experimental data, is successfully adopted to simulate overturning plunging breakers which give rise to dangerous impact loads when they break against wind turbine substructures. Emphasis is then placed on the random nature of the waves. Indeed, through a domain decomposition technique a global simulation framework embedding the numerical wave simulator into a more general stochastic environment is developed. The proposed model is meant as a contribution to meet the more and more pressing demand for research in the offshore wind energy sector as it permits taking into account dangerous effects on the structural response so as to increase the global structural safety level.
| Author | : |
| Publisher | : |
| Total Pages | : 0 |
| Release | : 2014 |
| Genre | : |
| ISBN | : |
Download Computation of Wave Loads under Multidirectional Sea States for Floating Offshore Wind Turbines: Preprint Book in PDF, ePub and Kindle
This paper focuses on the analysis of a floating wind turbine under multidirectional wave loading. Special attention is given to the different methods used to synthesize the multidirectional sea state. This analysis includes the double-sum and single-sum methods, as well as an equal-energy discretization of the directional spectrum. These three methods are compared in detail, including theergodicity of the solution obtained. From the analysis, the equal-energy method proved to be the most computationally efficient while still retaining the ergodicity of the solution. This method was chosen to be implemented in the numerical code FAST. Preliminary results on the influence of these wave loads on a floating wind turbine showed significant additional roll and sway motion of theplatform.
| Author | : Sungho Lee (Ph. D.) |
| Publisher | : |
| Total Pages | : 173 |
| Release | : 2012 |
| Genre | : |
| ISBN | : |
Download A Nonlinear Wave Load Model for Extreme and Fatigue Responses of Offshore Floating Wind Turbines Book in PDF, ePub and Kindle
Ocean energy is one of the most important sources of alternative energy and offshore floating wind turbines are considered viable and economical means of harnessing ocean energy. The accurate prediction of nonlinear hydrodynamic wave loads and the resulting nonlinear motion and tether tension is of crucial importance in the design of floating wind turbines. A new theoretical framework is presented for analyzing hydrodynamic forces on floating bodies which is potentially applicable in a wide range of problems in ocean engineering. The total fluid force acting on a floating body is obtained by the time rate of change of the impulse of the velocity potential flow around the body. This new model called Fluid Impulse Theory is used to address the nonlinear hydrodynamic wave loads and the resulting nonlinear responses of floating wind turbine for various wave conditions in a highly efficient and robust manner in time domain. A three-dimensional time domain hydrodynamic wave-body interaction computational solver is developed in the frame work of a boundary element method based on the transient free-surface Green-function. By applying a numerical treatment that takes the free-surface boundary conditions linearized at the incident wave surface and takes the body boundary condition satisfied on the instantaneous underwater surface of the moving body, it simulates a potential flow in conjunction with the Fluid Impulse Theory for nonlinear wave-body interaction problems of large-amplitude waves and motions in time domain. Several results are presented from the application of the Fluid Impulse Theory to the extreme and fatigue wave load model: the time domain analysis of nonlinear dynamic response of floating wind turbine for extreme wave events and the time domain analysis of nonlinear wave load for an irregular sea state followed by a power spectral density analysis.
| Author | : Joao Cruz |
| Publisher | : Springer |
| Total Pages | : 345 |
| Release | : 2016-08-20 |
| Genre | : Technology & Engineering |
| ISBN | : 3319293982 |
Download Floating Offshore Wind Energy Book in PDF, ePub and Kindle
This book provides a state-of-the-art review of floating offshore wind turbines (FOWT). It offers developers a global perspective on floating offshore wind energy conversion technology, documenting the key challenges and practical solutions that this new industry has found to date. Drawing on a wide network of experts, it reviews the conception, early design stages, load & structural analysis and the construction of FOWT. It also presents and discusses data from pioneering projects. Written by experienced professionals from a mix of academia and industry, the content is both practical and visionary. As one of the first titles dedicated to FOWT, it is a must-have for anyone interested in offshore renewable energy conversion technologies.
| Author | : Romain Pinguet |
| Publisher | : |
| Total Pages | : 0 |
| Release | : 2021 |
| Genre | : |
| ISBN | : |
Download Hydrodynamics of Semi-submersible Floater for Offshore Wind Turbines in Highly Nonlinear Waves Using Computational Fluid Dynamics (CFD), and Validation of Overset Meshing Technique in a Numerical Wave Tank Book in PDF, ePub and Kindle
The rapid emergence of Floating Offshore Wind Turbines (FOWT) has brought a strong demand for high-fidelity numerical methods to better predict the response of such structures under severe metocean conditions. In these scenarios, design standards suggest simplified approaches, but their applicability is limited, especially when considering complex geometries and/or nonlinear events. Moreover, experimental campaigns are expensive, and few field data are available. So, Computational Fluid Dynamics (CFD) could be a key asset in the design process of FOWT. This thesis aims to assess the ability of a CFD approach to model critical hydrodynamic aspects of semi-submersible FOWT. The overset meshing method built in the open-source software OpenFOAM® is used to handle the body motions. The wave generation and absorption toolbox waves2Foam is coupled with the overset solver to model the interaction between waves and the structure. The results are validated against experimental and numerical data from the literature. Convergence analysis and meshing methodologies of a 2D Numerical Wave Tank (NWT), with fixed and freely floating structures subjected to waves, are considered. Non-linearities are emphasized. The NWT is then extended in 3D to investigate the hydrodynamic response of the DeepCWind semi-submersible FOWT, designed by NREL. Forces and run-up are analyzed for fixed and anchored moving platforms. Wave induced motion and free decay tests are presented. The overset mesh method is also used to estimate the hydrodynamic coefficients resulting from the vertical forced motion of heave damping plate, widely used in FOWT designs.
| Author | : Odd M. Faltinsen |
| Publisher | : Cambridge University Press |
| Total Pages | : 0 |
| Release | : 2014-03-06 |
| Genre | : Technology & Engineering |
| ISBN | : 9781107646735 |
Download Sloshing Book in PDF, ePub and Kindle
This book presents sloshing with marine and land-based applications, with a focus on ship tanks. It also includes the nonlinear multimodal method developed by the authors and an introduction to computational fluid dynamics. Emphasis is also placed on rational and simplified methods, including several experimental results. Topics of special interest include antirolling tanks, linear sloshing, viscous wave loads, damping, and slamming. The book contains numerous illustrations, examples, and exercises.
