Coupled Dynamic Analysis Of Multiple Unit Floating Offshore Wind Turbine
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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
Coupled Dynamic Analysis Of Floating Offshore Wind Farms
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Author : Sangyun Shim
language : en
Publisher:
Release Date : 2010
Coupled Dynamic Analysis Of Floating Offshore Wind Farms written by Sangyun Shim and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2010 with categories.
During the past decade, the demand for clean renewable energy continues to rise drastically in Europe, the US, and other countries. Wind energy in the ocean can possibly be one of those future renewable clean energy sources as long it is economically feasible and technologically manageable. So far, most of the offshore wind farm research has been limited to fixed platforms in shallow-water areas. In the water depth deeper than 30m, however, floating-type wind farms tend to be more feasible. Then, the overall design and engineering becomes more complicated than fixed platforms including the coupled dynamics of platforms, mooring lines, and blades. In the present study, a numerical time-domain model has been developed for the fully coupled dynamic analysis of an offshore floating wind turbine system including blade-rotor dynamics and platform motions. As a test case, the TLP-type floater system with 3 blades of 70-m diameter designed by the National Renewable Energy Laboratory (NREL) is selected to analyze the dynamic coupling effects among floating system, mooring lines, and wind turbine. The performance of the selected system in a typical wind-wave-current condition has been simulated and analyzed. A similar study for the floater and rotor coupled dynamic analysis was conducted by MIT and NREL. However, in the present case, the dynamic coupling between platform and mooring lines are also considered in addition to the rotor-floater dynamic coupling. It is seen that the rotor-floater coupling effects increase with wind velocity and blade size. The increased coupling effects tend to increase the dynamic tension of TLP tethers. The developed technology and numerical tool are applicable to the new offshore floating wind farms planned in the future.
Fully Coupled Dynamic Analysis Of A Floating Wind Turbine System
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Author : Jon E. Withee
language : en
Publisher:
Release Date : 2004
Fully Coupled Dynamic Analysis Of A Floating Wind Turbine System written by Jon E. Withee and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2004 with Wind power categories.
The use of wind power is in a period of rapid growth worldwide and wind energy systems have emerged as a promising technology for utilizing offshore wind resources for the large scale generation of electricity Drawing upon the maturity of wind turbine and floater technologies developed by the wind energy and oil and gas industries, respectively, large offshore wind energy systems have been developed and are being proposed for operation in offshore areas where environmental restrictions are less restrictive, large wind resources exist, and open sea areas are available for wind farm development. A fully coupled dynamic analysis/technique was developed to predict the response of a floating wind turbine system in a stochastic wind and wave environment This technique incorporated both non-linear wave loading on the submerged floater and the aerodynamic loading on the wind turbine A tension leg spar buoy was designed to support the wind turbine This design was chosen due to its relatively small size and hence lower potential cost per wind turbine The system's tethers were attached to the ends of spokes which radiated out from the spar cylinder This arrangement of lines and spokes promised to be very stiff in the roll and pitch modes of motion.
Coupled Dynamic Analysis Of Large Scale Mono Column Offshore Wind Turbine With A Single Tether Hinged In Seabed
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Author : Jieyan Chen
language : en
Publisher:
Release Date : 2012
Coupled Dynamic Analysis Of Large Scale Mono Column Offshore Wind Turbine With A Single Tether Hinged In Seabed written by Jieyan Chen and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2012 with categories.
The increased interest in the offshore wind resource in both industry and academic and the extension of the wind field where offshore wind turbine can be deployed has stimulated quite a number of offshore wind turbines concepts. This thesis presents a design of mono-column platform supported for 5 MW baseline wind turbine developed by the National Renewable Energy Laboratory (NREL), with a single tether anchored to the seabed. The design, based on the pioneer concept SWAY®, results from parametric optimized design processes which account for important design considerations in the static and dynamic view, such as the stability, natural frequency, performance requirements as well as the economic feasibility. Fully coupled aero-hydro-servo-elastic model is established in the time-domain simulation tool FAST (Fatigue, Aerodynamics, Structures, and Turbulence) with the hydrodynamic coefficients from HydroGen, an indoor program providing same outputs as the commercial software WAMIT. The optimized model is verified by imitating the frequency-domain approach in FAST and thus comparing the results with the frequency-domain calculations. A number of simulations with various wind and wave conditions are run to explore the effect of wind speed and wave significant height in various water depths. By modifying the optimized model to a downwind turbine with the nacelle rigidly mounted on the tower and the single tether connected to the platform by a subsea swivel, the modified models are more closed to the original SWAY®-concept wind turbine. These models are compared based on the platform motion, tether tension, displacement, nacelle velocity and acceleration, resonant behavior as well as the damping of the coupled systems. The results of these comparisons prove the advantage of the modified model in performance. The modified model has also clarified itself a good candidate for deep water deployment.
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.
Floating Offshore Wind Energy
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Author : Joao Cruz
language : en
Publisher: Springer
Release Date : 2016-08-20
Floating Offshore Wind Energy written by Joao Cruz and has been published by Springer this book supported file pdf, txt, epub, kindle and other format this book has been release on 2016-08-20 with Technology & Engineering categories.
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.
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." --
Dynamic Response Analysis Of An Offshore Wind Turbine Supported By A Moored Semi Submersible Platform
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Author : Mohit Soni
language : en
Publisher:
Release Date : 2014
Dynamic Response Analysis Of An Offshore Wind Turbine Supported By A Moored Semi Submersible Platform written by Mohit Soni and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2014 with categories.
Wind energy, the fastest growing source of renewable energy, is a promising resource for power generation. Offshore wind energy, in particular,offers favorable conditions for power generation--high winds with low turbulence, minimal visual impacts and high generation capacities. Offshore wind turbines mounted on floating platforms are the most economical and viable solution for deep water sites. A semi-submersible platform is an appropriate floating platform for a deep water site, providing stability through high water-plane area. In the wind energy industry, there has been continuing interest in developing larger turbines. At Sandia National Laboratories (SNL), efforts have led to the development of a 13.2 MW wind turbine model with blades 100 meters in length, significantly larger than commercially available blades at present. Such a large wind turbine needs to be carefully analyzed and studied before it can be considered suitable for commercial purposes. The dynamic analysis of the SNL 13.2 MW wind turbine mounted on a moored semi-submersible platform is the subject of this study. This integrated 13.2 MW wind turbine system has been developed and its various physical properties have been studied in this and another associated study. The semi-submersible platform is developed using various modeling tools. For the wind turbine-platform system model developed, dynamic analyses are performed using simulation tools to understand the coupled behavior of the wind turbine and the platform. A reference site is chosen to define the environmental conditions, based on which the short-term extreme response of the offshore wind turbine is estimated. The system is loaded with selected combinations of winds and waves to assess controlling combinations of wind speeds and wave heights that influence the response. The influence of changes in model parameters on overall response is also studied.
Dynamic Analysis Of A 5 Megawatt Offshore Floating Wind Turbine
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Author : Evan Michael Harriger
language : en
Publisher:
Release Date : 2011
Dynamic Analysis Of A 5 Megawatt Offshore Floating Wind Turbine written by Evan Michael Harriger and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2011 with categories.
Offshore wind is a valuable source of renewable energy, as it is typically strong and steady. Turbines have been utilized offshore in parts of Europe and Asia, however only at shallow depths. Floating wind turbines must be implemented in deeper areas to be economical, but this technology is relatively new and untested. This paper describes a numerical analysis model that can be used to investigate the motion of a 5 MW floating turbine subjected to ocean conditions. Prototype designs for a spar buoy and barge platform are studied. The stiffness and damping effects brought about by the mooring lines are evaluated using a dynamic cable model. A boundary element model is used to calculate added mass and damping effects, as well as the forces on the structure caused by the wave-body interaction. The governing equations of motion include all the added mass, damping and stiffness components in the frequency domain. Response of the structure is found by solving the governing equation combined with a wave spectrum to represent actual ocean wave fields. Approximate bending moments at the base of each design are found by inputting the predicted base motion into a linear modal analysis model created in SAP2000. Based on the results found in this paper, incoming waves cause much greater motion of the barge design, especially in the pitching direction.
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.