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The Impact Of Coherent Turbulence On Wind Turbine Aeroelastic Response And Its Simulation
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Book Synopsis The Impact of Coherent Turbulence on Wind Turbine Aeroelastic Response and Its Simulation by : Neil Davis Kelley
Download or read book The Impact of Coherent Turbulence on Wind Turbine Aeroelastic Response and Its Simulation written by Neil Davis Kelley and published by . This book was released on 2005 with total page 19 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis The Impact of Coherent Turbulence on Wind Turbine Aeroelastic Response and Its Simulation by :
Download or read book The Impact of Coherent Turbulence on Wind Turbine Aeroelastic Response and Its Simulation written by and published by . This book was released on 2005 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Wind Energy - Impact of Turbulence by : Michael Hölling
Download or read book Wind Energy - Impact of Turbulence written by Michael Hölling and published by Springer Science & Business. This book was released on 2014-05-15 with total page 207 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents the results of the seminar “Wind Energy and the Impact of Turbulence on the Conversion Process” which was supported from three societies, namely the EUROMech, EAWE and ERCOFATC and took place in Oldenburg, Germany in spring 2012. The seminar was one of the first scientific meetings devoted to the common topic of wind energy and basic turbulence. The established community of researchers working on the challenging puzzle of turbulence for decades met the quite young community of researchers, who face the upcoming challenges in the fast growing field of wind energy applications. From the fluid mechanical point of view, wind turbines are large machines operating in the fully turbulent atmospheric boundary layer. In particular they are facing small-scale turbulent inflow conditions. It is one of the central puzzles in basic turbulence research to achieve a fundamental understanding of the peculiarities of small-scale turbulence. This book helps to better understand the resulting aerodynamics around the wind turbine’s blades and the forces transmitted into the machinery in this context of puzzling inflow conditions. This is a big challenge due to the multi-scale properties of the incoming wind field ranging from local flow conditions on the profile up to the interaction of wake flows in wind farms.
Book Synopsis Effects of Daytime Atmospheric Boundary Layer Turbulence on the Generation of Nonsteady Wind Turbine Loadings and Predictive Accuracy of Lower Order Models by : Adam Lavely
Download or read book Effects of Daytime Atmospheric Boundary Layer Turbulence on the Generation of Nonsteady Wind Turbine Loadings and Predictive Accuracy of Lower Order Models written by Adam Lavely and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Modern utility-scale wind turbines operate in the the lower atmospheric boundary layer (ABL), which is characterized by large gradients in mean velocity and temperature and the existence of strong coherent turbulence eddies that reflect the interaction between strong mean shear and vertical buoyancy driven by solar heating. The spatio-temporal velocity variations drive nonsteady loadings on wind turbines that contribute to premature wind turbine component fatigue failure, decreasing the levelized cost of (wind) energy (LCOE). The aims of the current comprehensive research program center on the quantification of the characteristics of the nonsteady loads resulting from the interactions between the coherent energy contain gin atmospheric turbulence eddies within the lower ABL as the eddies advect through the rotor plane and the rotating wind turbine blade encounter the internal turbulence structure of the atmospheric eddies.We focus on the daytime atmospheric boundary layer, where buoyancy due to surface heating interacts with shear to create coherent turbulence structures. Pseudo-spectral large eddy simulation (LES) is used to generate an equilibrium atmospheric boundary layer over flat terrain with uniform surface roughness characteristic of the Midwest on a typical sunny windy afternoon when the ABL can be approximated as quasi-steady. The energy-containing eddies are found to create advective time-responses of order 30-90 seconds with lateral spatial scales of order the wind turbine rotor diameter. Different wind turbine simulation methods of a representative utility scale turbine were applied using the atmospheric turbulence as inflow.We apply three different fidelity wind turbine simulation methods to quantify the extent to which lower order models are able to accurately predict the nonsteady loading due to atmospheric turbulence eddies advecting through the rotor plane and interacting with the wind turbine. The methods vary both the coupling to the atmospheric boundary layer and the way in which the blade geometry is resolved and sectional blade forces are calculated. The highest fidelity simulation resolves the blade geometry to capture unsteady boundary layer response and separation dynamics within a simulation of the atmospheric boundary layer coupling the effect of the turbine to the atmospheric inflow. The lower order models both use empirical look-up tables to predict the time changes in blade sectional forces as a function of time changes in local velocity vector. The actuator line method (ALM) is two-way coupled and feeds these blade forces back into a simulation of the atmospheric boundary layer. The blade element momentum theory (BEMT) is one-way coupled and models the effect of the turbine on the incoming velocity field. The coupling method and method of blade resolution are both found to have an effect on the ability to accurately predict sectional blade load response to nonsteady atmospheric turbulence. The BEMT cannot accurately predict the timing of the response changes as these are modulated by the wind turbine within the ABL simulations. The lower order models have increased blade sectional load range and temporal gradients due to their inability to accurately capture the temporal response of the blade geometry to inflow changes. Taking advantage of horizontal homogeneity to collect statistics, we investigate the time period required to create well converged statistics in the equilibrium atmospheric boundary layer and find whereas the 10-minute industry standard for `averages' retains variability of order 10%, the 10-minute average is an optimal choice. We compare the industry standard 10-minute averaging period. The residual variability within the 10-minute period to the National Renewable Energy Laboratory (NREL) Gearbox Reliability Collaborative (GRC) field test database to find that whereas the 10-minute window still contains large variability, it is, in some sense, optimal because averaging times much longer would be required to significantly reduce variability. Turbulence fluctuations in streamwise velocity are found to be the primary driver of temporal variations in local angles of attack and sectional blade loads. Based on this new understanding, we develop analyses to show that whereas rotor torque and thrust correlate well with upstream horizontal velocity averaged over the rotor disk, out-of-plane bending moment magnitude correlates with the asymmetry in the horizontal fluctuating velocity over the rotor disk. Consequentially, off-design motions of the drivetrain and gearbox shown with the GRC field test data are well predicted using an asymmetry index designed to capture the response of a three-bladed turbine to asymmetry in the rotor plane. The predictors for torque, thrust and out-of-plane bending moment are shown to correlate well to upstream rotor planes indicating that they may be applied to advanced feed-forward control methods such as forward-facing LIDAR used to detect velocity changes in front of a wind turbine. This has the potential to increase wind turbine reliability by using controls to reduce potentially detrimental load responses to incoming atmospheric turbulence and decrease the LCOE.
Book Synopsis Fundamentals of Materials for Energy and Environmental Sustainability by : David S. Ginley
Download or read book Fundamentals of Materials for Energy and Environmental Sustainability written by David S. Ginley and published by Cambridge University Press. This book was released on 2011-11-30 with total page 773 pages. Available in PDF, EPUB and Kindle. Book excerpt: How will we meet rising energy demands? What are our options? Are there viable long-term solutions for the future? Learn the fundamental physical, chemical and materials science at the heart of renewable/non-renewable energy sources, future transportation systems, energy efficiency and energy storage. Whether you are a student taking an energy course or a newcomer to the field, this textbook will help you understand critical relationships between the environment, energy and sustainability. Leading experts provide comprehensive coverage of each topic, bringing together diverse subject matter by integrating theory with engaging insights. Each chapter includes helpful features to aid understanding, including a historical overview to provide context, suggested further reading and questions for discussion. Every subject is beautifully illustrated and brought to life with full color images and color-coded sections for easy browsing, making this a complete educational package. Fundamentals of Materials for Energy and Environmental Sustainability will enable today's scientists and educate future generations.
Book Synopsis REDUCED-ORDER CHARACTERIZATION OF THE AEROELASTIC RESPONSE OF STALL-CONTROLLED WIND TURBINES UNDER ATMOSPHERIC TURBULENCE by :
Download or read book REDUCED-ORDER CHARACTERIZATION OF THE AEROELASTIC RESPONSE OF STALL-CONTROLLED WIND TURBINES UNDER ATMOSPHERIC TURBULENCE written by and published by . This book was released on 2020 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract : Wind, by its vary nature, varies with place and time, making energy conversion difficult. This calls for the development of improved technologies that efficiently harness energy from the available wind resource, and advanced control systems are a key research aspect of wind turbine technology. Such systems are needed to maximize the rotor's output power at wind speeds below the nominal value for the turbine, limit rotor power at wind speeds higher than the nominal, and reduce fluctuating loads on the turbine blades that may compromise their long-term operational life. Among the several families of control methods for wind turbines, Pitch and Stall are by far the most used in modern utility-scale machines. Both are based on altering the aerodynamic characteristics of the blade sections in order to control the forces which produce the rotor's torque, power, and thrust, and its deformation. A very popular control method to optimize power production and control is using Variable-Speed Wind Turbines (VSWT) a relatively new idea, which offers has a promising perspective for future applications. As with the classical Fixed-Speed (FS) stall method lowers the capital cost and reduces maintenance expenses, while at the same time, allows for a more efficient and precise control of power production. This research investigated the aeroselastic behavior of the stall-controlled rotors, studied the frequency content and time evolution of their oscillatory behavior, and gained a better understanding of the underlying physics. This calls for a wide range of experiments that assess the effects of rapid variations on the rotor's operational conditions, like gusts and turbulent fluctuations on the wind flow. To systematize this analysis, various gust conditions tested for different wind speeds. These are represented by pulses of different intensity, occurring suddenly in and otherwise constant wind regime. This allows us to observe the pure aero-elasto-inertial dynamics of the rotor's response. We will show the results from an extensive series of experiments analyzing the aeroelastic response of the rotor to wind speed fluctuations associated to the turbulent characteristics of the atmospheric boundary layer, focusing on obtaining a reduced-order characterization of the rotor's dynamics as an oscillatory system based on energy-transfer principles. Besides on its intrinsic scientific value, this aspect of the work presented here is of fundamental interest for researchers and engineers working on developing optimized control strategies for wind turbines. It allows for the critical elements of the rotor's dynamic behavior to be described as a reduced-order model that can be solved in real-time, an essential requirement for determining predictive control actions.
Book Synopsis Using Time-frequency and Wavelet Analysis to Assess Turbulence by :
Download or read book Using Time-frequency and Wavelet Analysis to Assess Turbulence written by and published by . This book was released on 2000 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: Large loading events on wind turbine rotor blades are often associated with transient bursts of coherent turbulent energy in the turbine inflow. These coherent turbulent structures are identified as peaks in the three-dimensional, instantaneous, turbulent shearing stress field. Such organized inflow structures and the accompanying rotor aeroelastic responses typically have time scales of only a few seconds and therefore do not lend themselves for analysis by conventional Fourier spectral techniques. Time-frequency analysis (and wavelet analysis in particular) offers the ability to more closely study the spectral decomposition of short period events such as the interaction of coherent turbulence with a moving rotor blade. In this paper, the authors discuss the initial progress in the application of time-frequency analysis techniques to the decomposition and interpretation of turbulence/rotor interaction. The authors discuss the results of applying both the continuous and discrete wavelet transforms for their application. Several examples are given of the techniques applied to both observed turbulence and turbine responses and those generated using numerical simulations. They found that the presence of coherent turbulent structures, as revealed by the inflow Reynolds stress field, is a major contributor to large load excursions. These bursts of coherent turbulent energy induce a broadband aeroelastic response in the turbine rotor as it passes through them.
Book Synopsis Assessing the Influence of Wake Dynamics on the Performance and Aeroelastic Behavior of Wind Turbines by : Krista Marie Kecskemety
Download or read book Assessing the Influence of Wake Dynamics on the Performance and Aeroelastic Behavior of Wind Turbines written by Krista Marie Kecskemety and published by . This book was released on 2012 with total page 181 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: While wind turbine farms are currently rapidly expanding, there are numerous technological challenges that must be overcome before wind energy represents a significant contributor to energy generation in the United States. One of the primary challenges is accurately accounting for the aerodynamic environment. This dissertation is focused on improving the aerodynamic modeling through the incorporation of wake effects. A comprehensive verification and validation of the NREL FAST code, which has been enhanced to include a Free Vortex Wake (FVW) model was conducted. The verification and validation is carried out through a comparison of wake geometry, blade lift distribution, wind turbine power and force and moment coefficients using a combination of Computational Fluid Dynamics (CFD) and experimental data. The results are also compared against Blade Element Momentum Theory (BEM), and results from an extensive experimental campaign by NREL on the prediction capabilities of wind turbine modeling tools. Results indicate that the enhanced aeroelastic code generally provides improved predictions. However, in several notable cases the predictions are only marginally improved, or even worse, than those generated using Blade Element Momentum Theory aerodynamics. After verification and validation of the model, the impact of including the free vortex wake model in the presence of turbulent flow was also examined. The inclusion of turbulence created large differences between BEM and FVW in predictions of rotor loading and power, however the amplitude of the turbulence did not have a large impact on the difference between the FVW and BEM. In addition to loading and power predictions, the structural response (tip deflections and root bending moments) of the wind turbine is investigated in the presence of turbulent inflow. The results indicate that the turbulence intensity and spectral model have a significant effect on the importance of the wake dynamics in modeling the tip deflections and root moments. From the dissertation results, it is concluded that modeling of the aerodynamic environment remains incomplete, even after inclusion of wake effects. One important aspect identified for future improvements is modeling of the unsteady aerodynamic lift characteristics of the rotor.
Book Synopsis Atmospheric and wake turbulence impacts on wind turbine fatigue loading by :
Download or read book Atmospheric and wake turbulence impacts on wind turbine fatigue loading written by and published by . This book was released on 2011 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Using Time-frequency and Wavelet Analysis to Assess Turbulence/rotor Interactions by : Neil Davis Kelley
Download or read book Using Time-frequency and Wavelet Analysis to Assess Turbulence/rotor Interactions written by Neil Davis Kelley and published by . This book was released on 1999 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Handbook of Wind Energy Aerodynamics by : Bernhard Stoevesandt
Download or read book Handbook of Wind Energy Aerodynamics written by Bernhard Stoevesandt and published by Springer Nature. This book was released on 2022-08-04 with total page 1495 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Book Synopsis The Great Plains Turbulence Environment by : Neil Davis Kelley
Download or read book The Great Plains Turbulence Environment written by Neil Davis Kelley and published by . This book was released on 2006 with total page 21 pages. Available in PDF, EPUB and Kindle. Book excerpt: This paper summarizes the known impacts of nocturnal turbulence on wind turbine performance and operations and discusses NREL's progress in numerically simulated coherent inflow turbulent conditions generated by atmospheric instabilities that are frequently associated with a Great Plains nocturnal low-level jet stream.
Book Synopsis Non-steady Dynamics of Atmospheric Turbulence Interaction with Wind Turbine Loadings Through Blade-boundary-layer-resolved CFD. by : Ganesh Vijayakumar
Download or read book Non-steady Dynamics of Atmospheric Turbulence Interaction with Wind Turbine Loadings Through Blade-boundary-layer-resolved CFD. written by Ganesh Vijayakumar and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Modern commercial megawatt-scale wind turbines occupy the lower 15-20% of the atmospheric boundary layer (ABL), the atmospheric surface layer (ASL). The current trend of increasing wind turbine diameter and hub height increases the interaction of the wind turbines with the upper ASL which contains spatio-temporal velocity variations over a wide range of length and time scales. Our interest is the interaction of the wind turbine with the energetic integral-scale eddies, since thesecause the largest temporal variations in blade loadings. The rotation of a wind turbine blade through the ABL causes fluctuations in the local velocity magnitude and angle of attack at different sections along the blade. The blade boundary layer responds to these fluctuations and in turn causes temporal transients in localsectional loads and integrated blade and shaft bending moments. While the integral scales of the atmospheric boundary layer are O(10-100m) in the horizontal with advection time scales of order tens of seconds, the viscous surface layer of the blade boundary layer is O(10 - 100 [mu]m) with time scales of order milliseconds. Thus, the response of wind turbine blade loadings to atmospheric turbulence is the resultof the interaction between two turbulence dynamical systems at extremely disparateranges of length and time scales. A deeper understanding of this interaction canimpact future approaches to improve the reliability of wind turbines in wind farms,and can underlie future improvements. My thesis centers on the development of a computational framework to simulate the interaction between the atmospheric and wind turbine blade turbulence dynamical systems using a two step one-way coupled approach. Pseudo-spectral large eddy simulation (LES) is used to generate a true (equilibrium) atmospheric boundary layer over a flat land with specified surface roughness and heating consistent with the stability state of the daytime lower troposphere. Using the data from the precursor simulation as inflow conditions, a second simulation is performed on a smaller domain around the wind turbine using finite volume CFD with a body-fitted grid to compute the unsteady blade loads in response to atmospheric turbulence. Analysis of the precursor LES shows that the advective time scales multiple rotation time scales of the rotor. From blade element momentum theory coupled with LES of the ABL, we find that the energy-containing eddies were found to cause large temporal fluctuations (±50%) in the integrated moments, primarilydue to changes in the local flow angle relative to the local chord sections.A low-dissipation pseudo-spectral algorithm was applied to the ABL LES. A finite volume algorithm was required to resolve the flow features around the complex blade geometry. The effect of the finite volume algorithm on the accuracy of it's prediction of the rough-surface ABL was assessed using the method of Brasseur and Wei [1]. We found that finite volume algorithms need finer horizontal grid resolution to retain the same accuracy as the corresponding pseudo-spectral simulations. Theseresults were used to design our computational framework to accurately propagate the turbulence eddies through the finite volume domain. The ability of our computational framework to capture blade boundary layerdynamics in response to atmospheric turbulence is intimately associated with the extreme care taken in the design of our grid and with the development of a new hybrid URANS-LES turbulence model. The new turbulence model blends a 1-equation LES subgrid model in the far field with the k-w-SST-SAS URANS model to the blade boundary layer adjacent to the blade surface. With this computational framework, we simulated a single rotating blade of the NREL-5MW wind turbine in the moderately convective daytime atmosphere using blade-boundary-layer-resolved CFD simulations. The analysis of load fluctuations on a single rotating blade in a daytime atmosphere using blade-boundary-layer-resolved CFD has yielded two key results:(1) Whereas non-steady blade loadings are generally described as the response tonon-steadiness in wind speed, our analysis show that time changes in wind vectordirection are a much greater contributor to load transients, and strongly impact boundary layer dynamics; (2) largest temporal variations in loadings result from three distinct dynamical responses with disparate time scales: advection of atmospheric eddies through the rotor at the minute time scale, blade response at the rotor rotation time scale (5s) and blade response to turbulence-induced forcingsas the blades traverse internal atmospheric eddy structure at sub-blade rotation time scales. In our simulations at rated wind speed, quasi-2D blade boundary layer separation is observed over most of the outer 50% of the blade with chordwise motions, correlated with time changes in relative wind vector angle, which itself is strongly correlated with changes in blade sectional and integrated loads. Thus, tools based on sectional "table lookups" like FAST [2] and Actuator Line Methods[3], improved using data from high-fidelity simulations and experiment, have the potential to capture the major fluctuations in integrated loads from daytime atmospheric turbulence.
Book Synopsis Scientific and Technical Aerospace Reports by :
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 602 pages. Available in PDF, EPUB and Kindle. Book excerpt: Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.
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 2018-07-25 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 Wind Turbine Load Dynamics in the Context of Intermittent Atmospheric Turbulence by : Carl Michael Schwarz
Download or read book Wind Turbine Load Dynamics in the Context of Intermittent Atmospheric Turbulence written by Carl Michael Schwarz and published by . This book was released on 2020 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In this work the impact of higher order statistics of wind on wind turbine loads, especially fatigue loads, is discussed. Non-Gaussian distributed wind velocity increments, which are related to the concept of turbulence intermittency, are the focal point of this thesis. Within this study, synthetic wind fields featuring Gaussian and non-Gaussian increment statistics are generated, utilizing a wind model based on Continuous-Time-Random-Walks. Subsequently, these fields are used as an input in a common wind turbine simulation. The resulting load responses are compared and analyzed with respect to the accumulated fatigue damage. In doing so, an increase in fatigue loading by approx. 5-10% for extreme coherent wind fields and selected load sensors is found. Additionally the dependency of this load enhancement on the coherence of the wind field is discussed. It is demonstrated that the intermittency effect decreases with the coherence.
Book Synopsis Development of an Aeroelastic Simulation for the Analysis of Vertical-axis Wind Turbines by : Gareth Marc Ferrari
Download or read book Development of an Aeroelastic Simulation for the Analysis of Vertical-axis Wind Turbines written by Gareth Marc Ferrari and published by . This book was released on 2012 with total page 486 pages. Available in PDF, EPUB and Kindle. Book excerpt: Like their horizontal-axis counterparts, as the blades of vertical-axis wind turbines increase in size they typically become relatively more flexible so a better understanding of their aeroelastic behaviour is required. This research addresses the challenges of large, flexible, vertical-axis wind turbines using methods previously unavailable, or impractical due to limited computational resources. A weakly-coupled aeroelastic simulation was developed to investigate the dynamic behaviour of vertical-axis wind turbines. The aeroelastic simulation comprised a free vortex wake model to represent the aerodynamics, and a multibody systems model to represent the structural dynamics, with the models coupled together via an interface. A modified version of the Beddoes- Leishman dynamic stall model was used to account for unsteady aerodynamic effects on the blades. The modal characteristics of the structural model were extracted using the Eigensystem Realisation Algorithm. The aerodynamic aspects of the simulation were validated against a wide range of experimental data. The structural aspects of the simulation were verified against an industry-standard multi-body systems package, and validated against a combination of analytical, numerical and experimental data. An extensive set of tests were conducted on the aerodynamic and structural models demonstrating that quite computationally undemanding methods for the computational parameters, including the time-step sizes and levels of blade discretisation, were capable of producing results very similar to those predicted using much more computationally demanding values. The aeroelastic simulation was used to conduct a number of numerical experiments designed to aid an investigation into how the aeroelastic behaviour of a large-scale baseline turbine configuration changed in response to various parameters. It was shown that the asymmetric loading along the blades, caused by a combination of the gravitational loads and the vertical variation in height of the wind speed, results in a periodic vertical rocking motion of the blades. This rocking motion occurred at a frequency of twice per revolution. It enabled new insight into the dynamic motion of VAWT blades. It was also found that the periodic rocking motion could be reduced by increasing the stiffness of the blades and reducing the linear density of the blades.
