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Sensitivity Of Modal Parameters Of An Offshore Wind Turbine To Operational And Environmental Factors A Numerical Study Preprint
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Book Synopsis Sensitivity of Modal Parameters of an Offshore Wind Turbine to Operational and Environmental Factors: A Numerical Study: Preprint by :
Download or read book Sensitivity of Modal Parameters of an Offshore Wind Turbine to Operational and Environmental Factors: A Numerical Study: Preprint written by and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The dynamics and performance of offshore wind turbines are sensitive to their structural properties, and in particular their modal parameters, i.e., natural frequencies, damping ratios and mode shapes. In this work, the sensitivity of the modal parameters of a 6 MW fixed-bottom offshore wind turbine to different operational and environmental conditions including wind speed and rotor speed is investigated. Effect of blade flexibility on the modal parameters of the system is also studied.
Book Synopsis Sensitivity of Modal Parameters of an Offshore Wind Turbine to Operational and Envrionmental Factors by : Nasim Partovi-Mehr
Download or read book Sensitivity of Modal Parameters of an Offshore Wind Turbine to Operational and Envrionmental Factors written by Nasim Partovi-Mehr and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis An Integrated Nonlinear Wind-Waves Model for Offshore Wind Turbines by : Enzo Marino
Download or read book An Integrated Nonlinear Wind-Waves Model for Offshore Wind Turbines written by Enzo Marino and published by Firenze University Press. This book was released on 2010 with total page 232 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Book Synopsis Validation of Numerical Models of the Offshore Wind Turbine from the Alpha Ventus Wind Farm Against Full-scale Measurements Within OC5 Phase III by : Wojciech Popko
Download or read book Validation of Numerical Models of the Offshore Wind Turbine from the Alpha Ventus Wind Farm Against Full-scale Measurements Within OC5 Phase III written by Wojciech Popko and published by . This book was released on 2019 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Offshore Wind Energy by : Finn Gunnar Nielsen
Download or read book Offshore Wind Energy written by Finn Gunnar Nielsen and published by Cambridge University Press. This book was released on 2024-03-31 with total page 395 pages. Available in PDF, EPUB and Kindle. Book excerpt: Addresses the scientific and technical challenges posed by the design of wind turbines for the offshore environment.
Book Synopsis Impact of Sea Ice Loads on Global Dynamics of Offshore Wind Turbines by : Wojciech Popko
Download or read book Impact of Sea Ice Loads on Global Dynamics of Offshore Wind Turbines written by Wojciech Popko and published by Fraunhofer Verlag. This book was released on 2020-12-10 with total page 240 pages. Available in PDF, EPUB and Kindle. Book excerpt: Support structures for offshore wind turbines (OWTs) are designed and certified site-specific based on the calculated load effects. These load effects originate from static, cyclic, stochastic, and transient loads from the met-ocean environment and rotating components of the wind turbine. The met-ocean environment of the Baltic Sea accounts for variable wind and marine conditions. Sea ice is part of marine conditions - which among others - should be included in the design process of OWT support structures. The load analysis and design of OWTs, including its components, rely on the time-domain based, coupled aero-hydro-servo-elastic simulation tools. Only this approach can provide an accurate prediction of the OWT dynamic response. Dynamic interaction between an OWT and external loads - including ice loads - cannot be disregarded as it may result in considerable loss of accuracy. A proper understanding of sea ice impact on the global dynamics of OWTs - involving the fully-integrated simulation approach - is necessary within the offshore wind research community, industry, and certification authorities.
Book Synopsis Development of an Offshore Specific Wind Power Forecasting System by : Melih Kurt
Download or read book Development of an Offshore Specific Wind Power Forecasting System written by Melih Kurt and published by kassel university press GmbH. This book was released on 2017-01-01 with total page 200 pages. Available in PDF, EPUB and Kindle. Book excerpt: This study explains the data preparation processes, plausibility checking of meteorological parameters, correction of met-mast wind speed, and also the determination of the nominal power of a wind farm using met-mast measurements. The wind speed correction of met-mast FINO1 is evaluated from the perspective of power produced by alpha ventus by using uncorrected and corrected measurements from this met-mast. Afterwards this data is used for the determination of nominal power for alpha ventus.
Book Synopsis Wind/Wave Misalignment in the Loads Analysis of a Floating Offshore Wind Turbine by :
Download or read book Wind/Wave Misalignment in the Loads Analysis of a Floating Offshore Wind Turbine written by and published by . This book was released on 2014 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt: Wind resources far from the shore and in deeper seas have encouraged the offshore wind industry to look into floating platforms. The International Electrotechnical Commission (IEC) is developing a new technical specification for the design of floating offshore wind turbines that extends existing design standards for land-based and fixed-bottom offshore wind turbines. The work summarized in this paper supports the development of best practices and simulation requirements in the loads analysis of floating offshore wind turbines by examining the impact of wind/wave misalignment on the system loads under normal operation. Simulations of the OC3-Hywind floating offshore wind turbine system under a wide range of wind speeds, significant wave heights, peak-spectral periods and wind/wave misalignments have been carried out with the aero-servo-hydro-elastic tool FAST [4]. The extreme and fatigue loads have been calculated for all the simulations. The extreme and fatigue loading as a function of wind/wave misalignment have been represented as load roses and a directional binning sensitivity study has been carried out. This study focused on identifying the number and type of wind/wave misalignment simulations needed to accurately capture the extreme and fatigue loads of the system in all possible metocean conditions considered, and for a down-selected set identified as the generic US East Coast site. For this axisymmetric platform, perpendicular wind and waves play an important role in the support structure and including these cases in the design loads analysis can improve the estimation of extreme and fatigue loads. However, most structural locations see their highest extreme and fatigue loads with aligned wind and waves. These results are specific to the spar type platform, but it is expected that the results presented here will be similar to other floating platforms.
Book Synopsis Floating Offshore Wind Energy by : Joao Cruz
Download or read book Floating Offshore Wind Energy written by Joao Cruz and published by Springer. This book was released on 2016-08-20 with total page 345 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Book Synopsis Aerodynamics of Wind Turbines, 2nd edition by : Martin O. L. Hansen
Download or read book Aerodynamics of Wind Turbines, 2nd edition written by Martin O. L. Hansen and published by Routledge. This book was released on 2013-05-13 with total page 192 pages. Available in PDF, EPUB and Kindle. Book excerpt: Aerodynamics of Wind Turbines is the established essential text for the fundamental solutions to efficient wind turbine design. Now in its second edition, it has been entirely updated and substantially extended to reflect advances in technology, research into rotor aerodynamics and the structural response of the wind turbine structure. Topics covered include increasing mass flow through the turbine, performance at low and high wind speeds, assessment of the extreme conditions under which the turbine will perform and the theory for calculating the lifetime of the turbine. The classical Blade Element Momentum method is also covered, as are eigenmodes and the dynamic behaviour of a turbine. The new material includes a description of the effects of the dynamics and how this can be modelled in an ?aeroelastic code?, which is widely used in the design and verification of modern wind turbines. Further, the description of how to calculate the vibration of the whole construction, as well as the time varying loads, has been substantially updated.
Book Synopsis Assessment and Nonlinear Modeling of Wave, Tidal and Wind Energy Converters and Turbines by : Madjid Karimirad
Download or read book Assessment and Nonlinear Modeling of Wave, Tidal and Wind Energy Converters and Turbines written by Madjid Karimirad and published by . This book was released on 2020-09-04 with total page 290 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Special Issue "Assessment and Nonlinear Modeling of Wave, Tidal, and Wind Energy Converters and Turbines" contributes original research to stimulate the continuing progress of the offshore renewable energy (ORE) field, with a focus on state-of-the-art numerical approaches developed for the design and analysis of ORE devices. Particularly, this collection provides new methodologies, analytical/numerical tools, and theoretical methods that deal with engineering problems in the ORE field of wave, wind, and current structures. This Special Issue covers a wide range of multidisciplinary aspects, such as the 1) study of generalized interaction wake model systems with elm variation for offshore wind farms; 2) a flower pollination method based on global maximum power point tracking strategy for point-absorbing type wave energy converters; 3) performance optimization of a Kirsten-Boeing turbine using a metamodel based on neural networks coupled with CFD; 4) proposal of a novel semi-submersible floating wind turbine platform composed of inclined columns and multi-segmented mooring lines; 5) reduction of tower fatigue through blade back twist and active pitch-to-stall control strategy for a semi-submersible floating offshore wind turbine; 6) assessment of primary energy conversion of a closed-circuit OWC wave energy converter; 7) development and validation of a wave-to-wire model for two types of OWC wave energy converters; 8) assessment of a hydrokinetic energy converter based on vortex-induced angular oscillations of a cylinder; 9) application of wave-turbulence decomposition methods on a tidal energy site assessment; 10) parametric study for an oscillating water column wave energy conversion system installed on a breakwater; 11) optimal dimensions of a semisubmersible floating platform for a 10 MW wind turbine; 12) fatigue life assessment for power cables floating in offshore wind turbines.
Book Synopsis Dynamic Analysis of an Offshore Wind Turbine Taking Into Account the Soil-foundation-structure Interaction by : Philip Alkhoury
Download or read book Dynamic Analysis of an Offshore Wind Turbine Taking Into Account the Soil-foundation-structure Interaction written by Philip Alkhoury and published by . This book was released on 2021 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Wind energy has received a vast attention in recent years. Multi-megawatt offshore wind turbines (OWTs) mounted on large diameter monopiles are being widely used nowadays in practice. There is a general acceptance that the overall weight of OWTs must be kept to a minimum to reduce their cost. This eventually resulted in a highly flexible slender structure that is dynamically-sensitive. The high sensitivity to the highly variable external loads demands special design consideration regarding the natural frequency of the OWT system which must be outside the excitations frequencies to avoid resonance. In addition to the resonance avoidance criterion, OWTs must verify stringent serviceability design requirements during their lifetime, which demand the consideration of a reliable numerical tool with an advanced soil constitutive model for the computation of the OWT dynamic responses. Modal and dynamic analyses of such complicated structures have been well-covered in literature using different aeroelastic simulation tools based on a limited number of degrees of freedom and/or make use of simplified assumptions related to the OWT superstructure, the soil-foundation interaction and the soil behavior. In response to these challenges, this thesis presents a three-dimensional finite element (FE) model that reflects the OWT behavior to a high degree of accuracy and that is used for the computation of the OWT modal and dynamic responses. Another aim of this thesis is to study the excessive vibration mitigation of OWTs. In this regard, this thesis presents a novel technique in which FE analysis is combined with a control system to study the real-time performance of an active tuned mass damper in reducing the OWT vibrations.
Book Synopsis Introduction to Operational Modal Analysis by : Rune Brincker
Download or read book Introduction to Operational Modal Analysis written by Rune Brincker and published by John Wiley & Sons. This book was released on 2015-06-17 with total page 376 pages. Available in PDF, EPUB and Kindle. Book excerpt: Comprehensively covers the basic principles and practice ofOperational Modal Analysis (OMA). Covers all important aspects that are needed to understand whyOMA is a practical tool for modal testing Covers advanced topics, including closely spaced modes, modeshape scaling, mode shape expansion and estimation of stress andstrain in operational responses Discusses practical applications of Operational ModalAnalysis Includes examples supported by MATLAB® applications Accompanied by a website hosting a MATLAB® toolbox forOperational Modal Analysis
Book Synopsis Wind Turbine Aerodynamics and Vorticity-Based Methods by : Emmanuel Branlard
Download or read book Wind Turbine Aerodynamics and Vorticity-Based Methods written by Emmanuel Branlard and published by Springer. This book was released on 2017-04-05 with total page 632 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book introduces the fundamentals of fluid-mechanics, momentum theories, vortex theories and vortex methods necessary for the study of rotors aerodynamics and wind-turbines aerodynamics in particular. Rotor theories are presented in a great level of details at the beginning of the book. These theories include: the blade element theory, the Kutta-Joukowski theory, the momentum theory and the blade element momentum method. A part of the book is dedicated to the description and implementation of vortex methods. The remaining of the book focuses on the study of wind turbine aerodynamics using vortex-theory analyses or vortex-methods. Examples of vortex-theory applications are: optimal rotor design, tip-loss corrections, yaw-models and dynamic inflow models. Historical derivations and recent extensions of the models are presented. The cylindrical vortex model is another example of a simple analytical vortex model presented in this book. This model leads to the development of different BEM models and it is also used to provide the analytical velocity field upstream of a turbine or a wind farm under aligned or yawed conditions. Different applications of numerical vortex methods are presented. Numerical methods are used for instance to investigate the influence of a wind turbine on the incoming turbulence. Sheared inflows and aero-elastic simulations are investigated using vortex methods for the first time. Many analytical flows are derived in details: vortex rings, vortex cylinders, Hill's vortex, vortex blobs etc. They are used throughout the book to devise simple rotor models or to validate the implementation of numerical methods. Several Matlab programs are provided to ease some of the most complex implementations.
Book Synopsis Dynamic Response and Reliability Analysis of an Offshore Wind Turbine Supported by a Semi-submersible Platform by : Edwin Thomas
Download or read book Dynamic Response and Reliability Analysis of an Offshore Wind Turbine Supported by a Semi-submersible Platform written by Edwin Thomas and published by . This book was released on 2015 with total page 198 pages. Available in PDF, EPUB and Kindle. Book excerpt: Wind Energy is the fastest growing renewable energy source in the world. The trend is expected to continue with falling costs of technology, energy security concerns and the need to address environmental issues. Offshore wind turbines have a few important advantages over land-based turbines; offshore sites experience stronger and less turbulent winds, there are fewer negative aesthetic impacts in an offshore location, there is greater ease in the transport of wind turbine components over sea than on land, etc. Large offshore wind turbines mounted atop floating platforms offer a viable solution for deepwater sites. Of the various floating platform concepts that are being considered, a moored semi-submersible platform is considered in this study. The dynamic response and reliability analysis of a 13.2~MW offshore wind turbine supported by a moored semi-submersible platform is the subject of this study. A model for this integrated system has been developed and its various physical, geometric, and dynamic properties have been studied in this and another associated study. Loads data for the extreme and fatigue analysis of such systems are generally attained by running time-domain simulations for a range of sea states that are representative of the expected site-specific metocean conditions. The selected site of interest in the North Sea has a water depth of 200 m. The Environmental Contour (EC) method is used to identify sea states of interest that are associated with a target return period (50 years). These sea states are considered in short-term (1-hour) simulations of the integrated turbine-platform-mooring system. The dynamic behavior of the integrated wind turbine system is studied. Critical sea states for the various response loads are identified and the sensitivity of the system to the metocean conditions is discussed. Estimation of 50-year response levels (for turbine loads, platform motions, and the mooring line tension at the fairlead) associated with the target probability is subsequently carried out using 2D and 3D Inverse First-Order Reliability Method (FORM) approaches.
Book Synopsis Frequency Domain Modeling and Multidisciplinary Design Optimization of Floating Offshore Wind Turbines by : Meysam Karimi
Download or read book Frequency Domain Modeling and Multidisciplinary Design Optimization of Floating Offshore Wind Turbines written by Meysam Karimi and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Offshore floating wind turbine technology is growing rapidly and has the potential to become one of the main sources of affordable renewable energy. However, this technology is still immature owing in part to complications from the integrated design of wind turbines and floating platforms, aero-hydro-servo-elastic responses, grid integrations, and offshore wind resource assessments. This research focuses on developing methodologies to investigate the technical and economic feasibility of a wide range of floating offshore wind turbine support structures. To achieve this goal, interdisciplinary interactions among hydrodynamics, aerodynamics, structure and control subject to constraints on stresses/loads, displacements/rotations, and costs need to be considered. Therefore, a multidisciplinary design optimization approach for minimum levelized cost of energy executed using parameterization schemes for floating support structures as well as a frequency domain dynamic model for the entire coupled system. This approach was based on a tractable framework and models (i.e. not too computationally expensive) to explore the design space, but retaining required fidelity/accuracy. In this dissertation, a new frequency domain approach for a coupled wind turbine, floating platform, and mooring system was developed using a unique combination of the validated numerical tools FAST and WAMIT. Irregular wave and turbulent wind loads were incorporated using wave and wind power spectral densities, JONSWAP and Kaimal. The system submodels are coupled to yield a simple frequency domain model of the system with a flexible moored support structure. Although the model framework has the capability of incorporating tower and blade structural DOF, these components were considered as rigid bodies for further simplicity here. A collective blade pitch controller was also defined for the frequency domain dynamic model to increase the platform restoring moments. To validate the proposed framework, predicted wind turbine, floating platform and mooring system responses to the turbulent wind and irregular wave loads were compared with the FAST time domain model. By incorporating the design parameterization scheme and the frequency domain modeling the overall system responses of tension leg platforms, spar buoy platforms, and semisubmersibles to combined turbulent wind and irregular wave loads were determined. To calculate the system costs, a set of cost scaling tools for an offshore wind turbine was used to estimate the levelized cost of energy. Evaluation and comparison of different classes of floating platforms was performed using a Kriging-Bat optimization method to find the minimum levelized cost of energy of a 5 MW NREL offshore wind turbine across standard operational environmental conditions. To show the potential of the method, three baseline platforms including the OC3-Hywind spar buoy, the MIT/NREL TLP, and the OC4-DeepCwind semisubmersible were compared with the results of design optimization. Results for the tension leg and spar buoy case studies showed 5.2% and 3.1% decrease in the levelized cost of energy of the optimal design candidates in comparison to the MIT/NREL TLP and the OC3-Hywind respectively. Optimization results for the semisubmersible case study indicated that the levelized cost of energy decreased by 1.5% for the optimal design in comparison to the OC4-DeepCwind.
Book Synopsis Probabilistic Hazard Analysis of Extreme Environmental Conditions for Offshore Wind Turbines by : Vahid Valamanesh
Download or read book Probabilistic Hazard Analysis of Extreme Environmental Conditions for Offshore Wind Turbines written by Vahid Valamanesh and published by . This book was released on 2015 with total page 139 pages. Available in PDF, EPUB and Kindle. Book excerpt: The development of renewable energy sources is a critical global need, and offshore wind energy is a particularly promising source. The Atlantic coast and Gulf of Mexico of the US, with large wind resources and proximity to major population centers, are natural places for such development, but so far the US still does not have a single utility-scale offshore wind turbine (OWT) in its waters. Europe, in contrast, installed its first OWT more than 30 years ago and currently has several gigawatts of installed capacity. Although experience in Europe provides important insight for the US, the presence of hurricane risk in the US means that new methods must be developed for assessing financial risk and designing/certifying OWTs for the hurricane-prone US coastal environment. This study presents research results and plans to advance understanding of the hurricane risk posed to OWTs. The dissertation herein addresses two overarching themes. The first theme is structural modeling of OWTs. While performance-based structural modeling of infrastructure subjected to natural hazards is a well-established field, modeling of OWTs presents some interesting challenges since an OWT can be considered as both a machine and a structure. In particular, the structural characteristics of an OWT vary significantly depending on the operational condition of the turbine. One of these characteristics, aerodynamic damping, is examined in detail in this work, and a closed-form equation for estimating the magnitude of aerodynamic damping for use in structural analysis software is proposed. The second theme is probabilistic characterization of hurricane-induced offshore hazard relevant to design and risk evaluations of OWTs. The offshore environment is a fascinating example of a multi-hazard situation where the hazards of extreme hurricane-induced wind, wave height, and wave period (among other hazards) are correlated to varying degrees. In this dissertation, the estimation of multi-hazard conditions relevant to OWTs is investigated and two approaches, one based on a jointly distributed model of multiple offshore hazards and another, simpler approach, based on independent distributions of multiple offshore hazards, are proposed to combine offshore hazards more realistically at recurrence periods relevant to design and risk assessment. As part of this second theme, probabilistic equations are statistically formulated for predicting wind speed and wave height during hurricanes. The equations are termed wind and wave prediction equations (WWPEs) and are analogous to ground motion prediction equations in probabilistic seismic hazard analysis. The equations are based on a statistical comparison between wind and wave measurements near the US Atlantic and Gulf of Mexico coastlines during hurricanes and two parametric models: Holland's model to estimate hurricane winds and Young's model to estimate hurricane waves.
