Analysis Of Floating Offshore Wind Turbine Hydrodynamics Using Coupled Cfd And Multibody Methods
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Analysis Of Floating Offshore Wind Turbine Hydrodynamics Using Coupled Cfd And Multibody Methods
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Author : Friedemann Beyer
language : en
Publisher:
Release Date : 2013
Analysis Of Floating Offshore Wind Turbine Hydrodynamics Using Coupled Cfd And Multibody Methods written by Friedemann Beyer and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2013 with categories.
Coupled Computational Fluid Dynamics Multibody Dynamics Method With Application To Wind Turbine Simulations
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Author : Yuwei Li
language : en
Publisher:
Release Date : 2014
Coupled Computational Fluid Dynamics Multibody Dynamics Method With Application To Wind Turbine Simulations written by Yuwei Li and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2014 with Computational fluid dynamics categories.
The implemented Mann wind turbulence model was validated both theoretically and statistically by comparing the generated stationary wind turbulent field with the theoretical one-point spectrum for the three components of the velocity fluctuations, and by comparing the expected statistics from the simulated turbulent field by CFD with the explicit wind turbulence inlet boundary from the Mann model. The proposed coupled CFD/MBD approach was applied to the conceptual NREL 5MW offshore wind turbine. Extensive simulations were performed in an increasing level of complexity to investigate the aerodynamic predictions, turbine performance, elastic blades, wind shear and atmospheric wind turbulence. Comparisons against the publicly available OC3 simulation results show good agreements between the CFD/MBD approach and the OC3 participants in time and frequency domains. Wind turbulence/turbine interaction was examined for the wake flow to analyze the influence of turbulent wind on wake diffusion. The Gearbox Reliability Collaborative project gearbox was up-scaled in size and added to the NREL 5MW turbine with the purpose of demonstrating drivetrain dynamics. Generator torque and blade pitch controllers were implemented to simulate realistic operational conditions of commercial wind turbines. Interactions between wind turbulence, rotor aerodynamics, elastic blades, drivetrain dynamics at the gear-level and servo-control dynamics were studied, showing the potential of the methodology to study complex aerodynamic/mechanic systems.
Coupled Dynamic Analysis Of Multiple Unit Floating Offshore Wind Turbine
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Author : Yoon Hyeok Bae
language : en
Publisher:
Release Date : 2013
Coupled Dynamic Analysis Of Multiple Unit Floating Offshore Wind Turbine written by Yoon Hyeok Bae and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2013 with categories.
In the present study, a numerical simulation tool has been developed for the rotor-floater-tether coupled dynamic analysis of Multiple Unit Floating Offshore Wind Turbine (MUFOWT) in the time domain including aero-blade-tower dynamics and control, mooring dynamics and platform motion. In particular, the numerical tool developed in this study is based on the single turbine analysis tool FAST, which was developed by National Renewable Energy Laboratory (NREL). For linear or nonlinear hydrodynamics of floating platform and generalized-coordinate-based FEM mooring line dynamics, CHARM3D program, hull-riser-mooring coupled dynamics program developed by Prof. M.H. Kim's research group during the past two decades, is incorporated. So, the entire dynamic behavior of floating offshore wind turbine can be obtained by coupled FAST-CHARM3D in the time domain. During the coupling procedure, FAST calculates all the dynamics and control of tower and wind turbine including the platform itself, and CHARM3D feeds all the relevant forces on the platform into FAST. Then FAST computes the whole dynamics of wind turbine using the forces from CHARM3D and return the updated displacements and velocities of the platform to CHARM3D. To analyze the dynamics of MUFOWT, the coupled FAST-CHARM3D is expanded more and re-designed. The global matrix that includes one floating platform and a number of turbines is built at each time step of the simulation, and solved to obtain the entire degrees of freedom of the system. The developed MUFOWT analysis tool is able to compute any type of floating platform with various kinds of horizontal axis wind turbines (HAWT). Individual control of each turbine is also available and the different structural properties of tower and blades can be applied. The coupled dynamic analysis for the three-turbine MUFOWT and five-turbine MUFOWT are carried out and the performances of each turbine and floating platform in normal operational condition are assessed. To investigate the coupling effect between platform and each turbine, one turbine failure event is simulated and checked. The analysis shows that some of the mal-function of one turbine in MUFOWT may induce significant changes in the performance of other turbines or floating platform. The present approach can directly be applied to the development of the remote structural health monitoring system of MUFOWT in detecting partial turbine failure by measuring tower or platform responses in the future. The electronic version of this dissertation is accessible from http://hdl.handle.net/1969.1/149465
Dynamics Modeling Simulation And Analysis Of A Floating Offshore Wind Turbine
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Author : Mohammed Khair Al-Solihat
language : en
Publisher:
Release Date : 2018
Dynamics Modeling Simulation And Analysis Of A Floating Offshore Wind Turbine written by Mohammed Khair Al-Solihat and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2018 with categories.
" Floating Offshore Wind Turbines (FOWTs) are a promising technology to harness the abundant offshore wind energy resources in open ocean areas. A FOWT consists of a floating platform, the moorings, and the wind turbine structure (tower + Rotor-Nacelle Assembly (RNA)). The main focus of this thesis is to develop multibody dynamic models that integrate the structural dynamics, and hydrostatic, hydrodynamic, aerodynamic and mooring system loads. Special efforts are also devoted to characterize the mooring and hydrostatic loads as main sources of systems stiffness that shapes the dynamic behavior of the system. Two approaches for modeling the platform/tower dynamics are developed, a rigid multibody model and a coupled rigid-flexible multibody model. Both models treat the platform, nacelle and rotor as six-degrees-of-freedom (6-DOF) rigid bodies. However, modeling the wind turbine tower dynamics differs between these approaches. The rigid model considers the tower as a 6-DOF rigid body while the flexible model represents the tower as a three-dimensional (3D) tapered damped Euler-Bernoulli beam undergoing coupled general rigid body and elastic motions. In both approaches, the wind turbine drivetrain dynamics is also considered to capture the rotor spin response. The equations of motions of both models are derived symbolically using Lagrange's equations. The hydrostatic restoring loads are evaluated through development of a novel nonlinear hydrostatic approach. This approach allows evaluating the exact hydrostatic force and moment and position of the center of buoyancy as function of the platform displacement and finite rotation. New exact expressions for the water plane area restoring moments are developed. The hydrostatic stiffness matrix at an arbitrary position and orientation of the platform is subsequently derived. A quasi-static approach is then developed to determine the cable tensions of the single-segment and multi-segment mooring system configurations proposed to moor the platform to the seabed. The approach uses different governing equations, depending on whether the mooring lines partially rest on the seabed; are suspended; or fully taut. The exact mooring stiffness is subsequently derived and the influence of several mooring system parameters on the mooring system stiffness is investigated. As an alternative to the quasi-static cable model, a lumped mass cable model incorporating the cable-seabed contact effect is developed to integrate the cable dynamics into the FOWT system dynamics. The equations of motion of the mooring line nodes are assembled for the two mooring system configurations under consideration. A new methodology is also presented to calculate the equilibrium profile of the mooring line lying on a seabed as desirable initial conditions for solving the discretized cable equations of motion. Finally, the theoretical models are implemented through a large simulation tool to analyze the dynamic behavior of the spar FOWT system under study. A series of simulations under defined external loads (load cases) are performed to validate the dynamic models. The simulation results are compared with similar results obtained from well-known offshore wind design codes. The simulation results are found to be in very good agreement with the reported results. Numerical experiments are also performed to investigate the influence of the tower flexibility, mooring system configuration, tower twist and cable dynamics on the system dynamic behavior. The results show that the system responses obtained from the rigid body model under-predict the platform yaw response and exhibit less damping than those obtained from the flexible model. It is also found that the mooring system configuration choice does not influence the platform roll and pitch responses or tower elastic deflections." --
Coupled Dynamic Modeling Of Floating Wind Turbine Systems
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Author :
language : en
Publisher:
Release Date : 2006
Coupled Dynamic Modeling Of Floating Wind Turbine Systems written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2006 with categories.
This article presents a collaborative research program that the Massachusetts Institute of Technology (MIT) and the National Renewable Energy Laboratory (NREL) have undertaken to develop innovative and cost-effective floating and mooring systems for offshore wind turbines in water depths of 10-200 m. Methods for the coupled structural, hydrodynamic, and aerodynamic analysis of floating wind turbine systems are presented in the frequency domain. This analysis was conducted by coupling the aerodynamics and structural dynamics code FAST [4] developed at NREL with the wave load and response simulation code WAMIT (Wave Analysis at MIT) [15] developed at MIT. Analysis tools were developed to consider coupled interactions between the wind turbine and the floating system. These include the gyroscopic loads of the wind turbine rotor on the tower and floater, the aerodynamic damping introduced by the wind turbine rotor, the hydrodynamic damping introduced by wave-body interactions, and the hydrodynamic forces caused by wave excitation. Analyses were conducted for two floater concepts coupled with the NREL 5-MW Offshore Baseline wind turbine in water depths of 10-200 m: the MIT/NREL Shallow Drafted Barge (SDB) and the MIT/NREL Tension Leg Platform (TLP). These concepts were chosen to represent two different methods of achieving stability to identify differences in performance and cost of the different stability methods. The static and dynamic analyses of these structures evaluate the systems' responses to wave excitation at a range of frequencies, the systems' natural frequencies, and the standard deviations of the systems' motions in each degree of freedom in various wind and wave environments. This article in various wind and wave environments. This article explores the effects of coupling the wind turbine with the floating platform, the effects of water depth, and the effects of wind speed on the systems' performance. An economic feasibility analysis of the two concepts was also performed. Key cost components included the material and construction costs of the buoy; material and installation costs of the tethers, mooring lines, and anchor technologies; costs of transporting and installing the system at the chosen site; and the cost of mounting the wind turbine to the platform. The two systems were evaluated based on their static and dynamic performance and the total system installed cost. Both systems demonstrated acceptable motions, and have estimated costs of $1.4-$1.8 million, not including the cost of the wind turbine, the power electronics, or the electrical transmission.
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
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Author : Romain Pinguet
language : en
Publisher:
Release Date : 2021
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 written by Romain Pinguet and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2021 with categories.
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.
Handbook Of Wind Energy Aerodynamics
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Author : Bernhard Stoevesandt
language : en
Publisher: Springer Nature
Release Date : 2022-08-04
Handbook Of Wind Energy Aerodynamics written by Bernhard Stoevesandt and has been published by Springer Nature this book supported file pdf, txt, epub, kindle and other format this book has been release on 2022-08-04 with Technology & Engineering categories.
This handbook provides both a comprehensive overview and deep insights on the state-of-the-art methods used in wind turbine aerodynamics, as well as their advantages and limits. The focus of this work is specifically on wind turbines, where the aerodynamics are different from that of other fields due to the turbulent wind fields they face and the resultant differences in structural requirements. It gives a complete picture of research in the field, taking into account the different approaches which are applied. This book would be useful to professionals, academics, researchers and students working in the field.
Mare Wint
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Author : Wiesław Ostachowicz
language : en
Publisher: Springer
Release Date : 2016-08-30
Mare Wint written by Wiesław Ostachowicz and has been published by Springer this book supported file pdf, txt, epub, kindle and other format this book has been release on 2016-08-30 with Technology & Engineering categories.
This book provides a holistic, interdisciplinary overview of offshore wind energy, and is a must-read for advanced researchers. Topics, from the design and analysis of future turbines, to the decommissioning of wind farms, are covered. The scope of the work ranges from analytical, numerical and experimental advancements in structural and fluid mechanics, to novel developments in risk, safety & reliability engineering for offshore wind.The core objective of the current work is to make offshore wind energy more competitive, by improving the reliability, and operations and maintenance (O&M) strategies of wind turbines. The research was carried out under the auspices of the EU-funded project, MARE-WINT. The project provided a unique opportunity for a group of researchers to work closely together, undergo multidisciplinary doctoral training, and conduct research in the area of offshore wind energy generation. Contributions from expert, external authors are also included, and the complete work seeks to bridge the gap between research and a rapidly-evolving industry.
Comparison Of Methods For The Computation Of Wave Forcing
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Author : Olga Glöckner
language : en
Publisher: GRIN Verlag
Release Date : 2018-05-18
Comparison Of Methods For The Computation Of Wave Forcing written by Olga Glöckner and has been published by GRIN Verlag this book supported file pdf, txt, epub, kindle and other format this book has been release on 2018-05-18 with Technology & Engineering categories.
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.
The Effect Of Second Order Hydrodynamics On Floating Offshore Wind Turbines
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Author : Line Roald
language : en
Publisher:
Release Date : 2013
The Effect Of Second Order Hydrodynamics On Floating Offshore Wind Turbines written by Line Roald and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2013 with categories.