Download or read book Near wake Flow Dynamics of a Horizontal Axis Wind Turbine written by Pooyan Hashemi Tari and published by . This book was released on 2012 with total page 282 pages. Available in PDF, EPUB and Kindle. Book excerpt: Experiments have been conducted in a large wind tunnel set-up in order to study the flow structures within the near-wake region of a horizontal axis wind turbine. Particle Image Velocimetry (PIV) has been employed to quantify the mean and turbulent components of the flow field. The measurements have been performed in multiple adjacent horizontal planes in order to cover the area behind the rotor in a large radial interval, at several locations downstream of the rotor. The measurements were phase-locked in order to facilitate the re-construction of the three-dimensional flow field. Acquiring uniform particle distribution in the measurement planes as well as proper calibration for the process of patching the adjacent measurement planes were the major issues influencing the PIV measurements. The results demonstrate the successful implementation of the PIV technique and the associated post-processing to accurately construct the flow field in the near-wake of a HAWT in a large wind tunnel setup. The mean velocity and turbulence characteristics clearly correlate with the near-wake vortex dynamics and in particular with the helical structure of the flow, formed shortly behind the turbine rotor. The radial velocity is low at the mid section of the blade and increases towards the tip. Close to the rotor and close to the blade tip and root regions the mean and turbulent characteristics of the flow are highly dependent on the azimuth angle of blade due to the tip and root vortices. Further from the rotor, the characteristics of the flow become phase independent. This can be attributed to the breakdown of the vortical structure of the flow, resulting from the turbulent diffusion. In general, the highest levels of turbulence are observed in shear layer around the tip of the blades, which decrease rapidly downstream. The shear zone grows in the radial direction as the iv wake moves axially, resulting in velocity recovery toward the centre of the rotor due to momentum transport. These findings are important in wind farm studies, where it is essential to determine the region of influence of the wake of each wind turbine, to study the interaction of wind turbines in the farm. The findings are also significant, as they point out that in the far wake region, the turbulent characteristics are independent of azimuth angle of the blade, which suggests the possibility of generating simple and robust wind turbine wake models for wind farm analysis. In addition to quantification of mean and turbulent velocity field, the capability and limitation of the Blade Element Momentum (BEM) method in predicting axial velocity profiles at the location of the rotor disc has been assessed. For this purpose, the profiles obtained from PIV measurements have been compared with those acquired from the classical BEM method, as well as with the improved method which involves series of corrections, including tip loss, stall delay and thrust coefficient corrections. In general, the comparison shows good qualitative agreement between velocity profiles obtained from PIV measurements and those obtained by BEM method, when the corrections are applied. Moreover, the PIV results have also been compared with the results obtained from the velocity measurements performed by previous investigators in small wind tunnel set-ups, in order to assess the scaling effects, and in particular the effect of local chord Reynolds number. The tip speed ratio is considered to be similar for all measurement to satisfy the kinematic similarity requirement. The comparison shows that the axial velocity profiles are highly dependent on Reynolds number. This is an important finding in terms of simulating scaled models of wind turbines and wind farms in wind tunnel settings.
Download or read book Investigation of Near Wake Flow Structure of a Horizontal Axis Wind Turbine Using Particle Image Velocimetry written by Kevin Tom and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Wind Turbine Design written by Ion Paraschivoiu and published by Presses inter Polytechnique. This book was released on 2002 with total page 472 pages. Available in PDF, EPUB and Kindle. Book excerpt: The depletion of global fossil fuel reserves combined with mounting environmental concerns has served to focus attention on the development of ecologically compatible and renewable alternative sources of energy. Wind energy, with its impressive growth rate of 40% over the last five years, is the fastest growing alternate source of energy in the world since its purely economic potential is complemented by its great positive environmental impact. The wind turbine, whether it may be a Horizontal Axis Wind Turbine (HAWT) or a Vertical Axis Wind Turbine (VAWT), offers a practical way to convert the wind energy into electrical or mechanical energy. Although this book focuses on the aerodynamic design and performance of VAWTs based on the Darrieus concept, it also discusses the comparison between HAWTs and VAWTs, future trends in design and the inherent socio-economic and environmental friendly aspects of wind energy as an alternate source of energy.
Download or read book Wind Turbine Aerodynamic Performance Calculation written by Tongguang Wang and published by Springer Nature. This book was released on 2023-12-15 with total page 241 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book deals with horizontal-axis wind turbine aerodynamic performance prediction methods. It focuses on the traditional and newly-developed methods for the wind turbine aerodynamic performance calculation. The fundamental theories of fluid mechanics essential for understanding the other parts of this book are firstly introduced in Part I, followed by the blade element momentum theory in Part II, with special attentions to a systematic review of various correction models. Part III is mainly about the prescribed and free vortex wake methods, while the state-of-art computational fluid dynamics (CFD) methods are detailed in Part IV. Part III thoroughly describes the prescribed and free vortex wake methods which are still of great importance towards realistic investigation of wind turbine performance. Despite the highly computational cost, the CFD methods in Part IV have received increasing interest from the academic community since they provide more detailed information about the flow field around the wind turbine. This has shed a light in combination with the correction models introduced in Part II on more advanced research for wind turbine. This book is intended for researchers and students interested in aerodynamics of wind turbine and is particularly suitable for practicing engineers in wind energy. Readers can gain a comprehensive understanding in both classical and up-to-date methods for the study of wind turbine aerodynamics. The authors hope that this book can promote the research and development of wind turbines.
Download or read book Wind Energy Handbook written by Tony L. Burton and published by John Wiley & Sons. This book was released on 2021-04-19 with total page 1016 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fully updated and authoritative reference to wind energy technology written by leading academic and industry professionals The newly revised Third Edition of the Wind Energy Handbook delivers a fully updated treatment of key developments in wind technology since the publication of the book’s Second Edition in 2011. The criticality of wakes within wind farms is addressed by the addition of an entirely new chapter on wake effects, including ‘engineering’ wake models and wake control. Offshore, attention is focused for the first time on the design of floating support structures, and the new ‘PISA’ method for monopile geotechnical design is introduced. The coverage of blade design has been completely rewritten, with an expanded description of laminate fatigue properties and new sections on manufacturing methods, blade testing, leading-edge erosion and bend-twist coupling. These are complemented by new sections on blade add-ons and noise in the aerodynamics chapters, which now also include a description of the Leishman-Beddoes dynamic stall model and an extended introduction to Computational Fluid Dynamics analysis. The importance of the environmental impact of wind farms both on- and offshore is recognized by expanded coverage, and the requirements of the Grid Codes to ensure wind energy plays its full role in the power system are described. The conceptual design chapter has been extended to include a number of novel concepts, including low induction rotors, multiple rotor structures, superconducting generators and magnetic gearboxes. References and further reading resources are included throughout the book and have been updated to cover the latest literature. As in previous editions, the core subjects constituting the essential background to wind turbine and wind farm design are covered. These include: The nature of the wind resource, including geographical variation, synoptic and diurnal variations, and turbulence characteristics The aerodynamics of horizontal axis wind turbines, including the actuator disc concept, rotor disc theory, the vortex cylinder model of the actuator disc and the Blade-Element/Momentum theory Design loads for horizontal axis wind turbines, including the prescriptions of international standards Alternative machine architectures The design of key components Wind turbine controller design for fixed and variable speed machines The integration of wind farms into the electrical power system Wind farm design, siting constraints, and the assessment of environmental impact Perfect for engineers and scientists learning about wind turbine technology, the Wind Energy Handbook will also earn a place in the libraries of graduate students taking courses on wind turbines and wind energy, as well as industry professionals whose work requires a deep understanding of wind energy technology.
Download or read book The Aerodynamics and Near Wake of an Offshore Floating Horizontal Axis Wind Turbine written by Thomas Sebastian and published by . This book was released on 2012 with total page 235 pages. Available in PDF, EPUB and Kindle. Book excerpt: Offshore floating wind turbines represent the future of wind energy. However, significant challenges must be overcome before these systems can be widely used. Because of the dynamics of offshore floating wind turbines -- surge, sway, heave, roll, pitch, and yaw -- and the resulting interactions between the rotor and generated wake, the aerodynamic analysis methods and design codes that have found wide use throughout the wind energy industry may be inadequate. Application of these techniques to offshore floating wind turbine aerodynamics may result in off-optimal designs, effectively handicapping these next-generation systems, thereby minimizing their full potential. This dissertation will demonstrate that the aerodynamics of offshore floating wind turbines are sufficiently different from conventional offshore and onshore wind turbines, warranting the use of higher fidelity analysis approaches. It will outline the development and validation of a free vortex wake code, the Wake Induced Dynamics Simulator, or WInDS, which uses a more physically realistic Lagrangian approach to modeling complex rotor-wake interactions. Finally, results from WInDS simulations of various offshore floating wind turbines under different load conditions will be presented. The simulation results indicate that offshore floating wind turbine aerodynamics are more complex than conventional offshore or onshore wind turbines and require higher fidelity analysis approaches to model adequately. Additionally, platform pitching modes appear to drive the most aerodynamically-significant motions, followed by yawing modes. Momentum balance approaches are shown to be unable to accurately model these dynamic systems, and the associated dynamic inflow methods respond to velocity changes at the rotor incorrectly. Future offshore floating wind turbine designs should strive to either minimize platform motions or be complementarily optimized, via higher fidelity aerodynamic analysis techniques, to account for them. It is believed that this dissertation is the first in-depth study of offshore floating wind turbine aerodynamics and the applicability of various analysis methods.
Download or read book Numerical Computation of Wind Turbine Flows and Fluid Problem by OpenFOAM and ANSYS written by Yi-Ching Wang and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Wind energy is the mainstream source of clean and renewable energy and it is also the fastest-growing source of sustainable energy in the world. In the Global Wind Energy Council's report in 2014, wind industry grew 44% worldwide. In order to optimize the efficiency of wind farms, it is important to observe wake interactions among wind turbines. Computational mathematics and mechanics provide fundamental methods and tools for simulating physical processes. Numerical computation can offer important insights and data that are either difficult or expensive to measure or to perform tests experimentally. In this dissertation, we use Computational Fluid Dynamics (CFD) software OpenFOAM and ANSYS FLUENT to simulate the wake effect of Horizontal Axis Wind Turbines (HAWT) and related problems. Numerical simulation can also help us comprehend and control man-made disasters. Air craft crashworthiness and human survivability are of utmost concerns in any emergency landing situation. Motivated by the air incidents lately, the disappearance of Malaysia Airlines Flight MH370 in March 2014 and Germanwings Flight 9525 crash in March 2015, we use Computational Structural Dynamics (CSD) software ANSYS Explicit Dynamics and LS-DYNA to try different numerical simulations of Airbus A320 crashing into a wall and compare the results to the reality. We calculate three CFD problems in this dissertation: lid-driven problems, one turbine wake problem, and two serial turbines wake problem. We simulate a lid-driven flow in both two- (2D) and three-dimension (3D) to compare the simulation capability of the three turbulence modelings, i.e., Direct Numerical Simulation (DNS), Large Eddy Simulation (LES), and Reynolds-Averaged Navier-Stokes Equations Simulation (RANS) by OpenFOAM. Among these three turbulence models, we can find that LES is capable of capturing more details of turbulence flow. We simulate the airflow effect of one wind turbine with both fixed angular velocity and wind-driven case, run benchmark tests based on NRELs reports, and compare the numerical results under the same condition by OpenFOAM and FLUENT. For the fixed angular velocity case, we use wind speed 8 m/s and angular velocity of the wind turbine 75 deg/s. For the wind-driven case, we use wind speed 8 m/s and 16 m/s and the angular velocity of the wind turbine calculated by FLUENT converges faster than OpenFOAM case. We simulate the interactions of wake flow for two serial wind turbines by FLUENT. We use wind speed 8 m/s and angular velocity of the wind turbine 75 deg/s. The wake of former turbine affects the rear one and the diffusion of flow caused by two turbines can be seen clearly. For both one and two serial turbines problems, the turbulence model RANS [lowercase kappa][lowercase epsilon] is used. We calculate and simulate Airbus A320 crashing into a wall by ANSYS Explicit Dynamics and LS-DYNA. For ANSYS Explicit Dynamics, we use the angle of approach 0°, 15°, and 30°. For LS-DYNA, we only test the pitch angles 0°. For all cases, we use the speed of aircarft 200 m/s. The deformation of both aircraft and wall can be seen clearly. The electronic version of this dissertation is accessible from http://hdl.handle.net/1969.1/155665
Download or read book Low Speed Aerodynamics written by Joseph Katz and published by Cambridge University Press. This book was released on 2001-02-05 with total page 636 pages. Available in PDF, EPUB and Kindle. Book excerpt: Low-speed aerodynamics is important in the design and operation of aircraft flying at low Mach number, and ground and marine vehicles. This 2001 book offers a modern treatment of the subject, both the theory of inviscid, incompressible, and irrotational aerodynamics and the computational techniques now available to solve complex problems. A unique feature of the text is that the computational approach (from a single vortex element to a three-dimensional panel formulation) is interwoven throughout. Thus, the reader can learn about classical methods of the past, while also learning how to use numerical methods to solve real-world aerodynamic problems. This second edition has a new chapter on the laminar boundary layer (emphasis on the viscous-inviscid coupling), the latest versions of computational techniques, and additional coverage of interaction problems. It includes a systematic treatment of two-dimensional panel methods and a detailed presentation of computational techniques for three-dimensional and unsteady flows. With extensive illustrations and examples, this book will be useful for senior and beginning graduate-level courses, as well as a helpful reference tool for practising engineers.
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.
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.
Download or read book Understanding Unsteady Aerodynamics of Modern Wind Turbines Using High Fidelity Computational Fluid Dynamics Simulation written by Abdul Bari Syed and published by . This book was released on 2016 with total page 186 pages. Available in PDF, EPUB and Kindle. Book excerpt: As the demand for renewable energy sources has expanded exponentially, a renewed interest for modern wind turbines has been seen recently. In this study, an unsteady aerodynamic analysis of modern wind turbines i.e. 5-MW offshore horizontal axis wind turbine (HAWT) and an innovative hybrid vertical axis wind turbine (VAWT) is performed. Aerodynamic loadings from the 3D offshore HAWT are calculated. The flow physics around the rotors of the turbines and wake formation behind the wind turbine is studied. Energy harvesting efficiency of 89.02% of the Betz limit has been achieved for this 5-MW offshore wind turbine. Similarly, a 2D unsteady high fidelity computational fluid dynamics analysis approach is carried out to investigate the performance characteristics of an innovative Hybrid Darrieus Modified-Savonius (HDMS) VAWT. As a first step, the performance comparison of Darrieus, Savonius, modified-Savonius (MS) and HDMS VAWT is performed for better understanding of the unsteady flow physics. Then a systematic analysis on HDMS VAWT for torque and power coefficients is conducted for varied wind speeds and tip speed ratios (TSRs). Flow analysis for velocity, pressure and vorticity distribution is carried out, which provides deep insight into rotor performance.
Download or read book Data Report written by A. M Talmon and published by . This book was released on 1985 with total page 110 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Wind Energy Handbook written by Tony Burton and published by John Wiley & Sons. This book was released on 2011-06-13 with total page 784 pages. Available in PDF, EPUB and Kindle. Book excerpt: Named as one of Choice's Outstanding Academic Titles of 2012 Every year, Choice subject editors recognise the most significant print and electronic works reviewed in Choice during the previous calendar year. Appearing annually in Choice's January issue, this prestigious list of publications reflects the best in scholarly titles and attracts extraordinary attention from the academic library community. The authoritative reference on wind energy, now fully revised and updated to include offshore wind power A decade on from its first release, the Wind Energy Handbook, Second Edition, reflects the advances in technology underpinning the continued expansion of the global wind power sector. Harnessing their collective industrial and academic expertise, the authors provide a comprehensive introduction to wind turbine design and wind farm planning for onshore and offshore wind-powered electricity generation. The major change since the first edition is the addition of a new chapter on offshore wind turbines and offshore wind farm development. Opening with a survey of the present state of offshore wind farm development, the chapter goes on to consider resource assessment and array losses. Then wave loading on support structures is examined in depth, including wind and wave load combinations and descriptions of applicable wave theories. After sections covering optimum machine size and offshore turbine reliability, the different types of support structure deployed to date are described in turn, with emphasis on monopiles, including fatigue analysis in the frequency domain. Final sections examine the assessment of environmental impacts and the design of the power collection and transmission cable network. New coverage features: turbulence models updated to reflect the latest design standards, including an introduction to the Mann turbulence model extended treatment of horizontal axis wind turbines aerodynamics, now including a survey of wind turbine aerofoils, dynamic stall and computational fluid dynamics developments in turbine design codes techniques for extrapolating extreme loads from simulation results an introduction to the NREL cost model comparison of options for variable speed operation in-depth treatment of individual blade pitch control grid code requirements and the principles governing the connection of large wind farms to transmission networks four pages of full-colour pictures that illustrate blade manufacture, turbine construction and offshore support structure installation Firmly established as an essential reference, Wind Energy Handbook, Second Edition will prove a real asset to engineers, turbine designers and wind energy consultants both in industry and research. Advanced engineering students and new entrants to the wind energy sector will also find it an invaluable resource.
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.
Download or read book A Computational Aeroacoustic Investigation of a Horizontal Axis Wind Turbine written by Matthew Levins and published by . This book was released on 2017 with total page 67 pages. Available in PDF, EPUB and Kindle. Book excerpt: Author's abstract: The aerodynamic and acoustic characteristics of a horizontal axis wind turbine was computationally investigated. The Computational Fluid Dynamics model of the horizontal axis wind turbine was validated with experimental data for a range of wind speeds and tip pitch angles. In addition, a mesh sensitivity analysis was performed to verify a grid independent solution. Steady state simulations were performed to validate the flow behavior over the airfoil section while transient simulations were performed in order to predict acoustic noise. The acoustic noise of the rotor was predicted at locations downstream of the rotor in the wake region. Higher tip pitch angles were found to result in less noise.
Download or read book Aerodynamics of Wind Turbines written by Sven Schmitz and published by John Wiley & Sons. This book was released on 2020-01-28 with total page 334 pages. Available in PDF, EPUB and Kindle. Book excerpt: A review of the aerodynamics, design and analysis, and optimization of wind turbines, combined with the author’s unique software Aerodynamics of Wind Turbines is a comprehensive introduction to the aerodynamics, scaled design and analysis, and optimization of horizontal-axis wind turbines. The author –a noted expert on the topic – reviews the fundamentals and basic physics of wind turbines operating in the atmospheric boundary layer. He then explores more complex models that help in the aerodynamic analysis and design of turbine models. The text contains unique chapters on blade element momentum theory, airfoil aerodynamics, rotational augmentation, vortex-wake methods, actuator-line modeling, and designing aerodynamically scaled turbines for model-scale experiments. The author clearly demonstrates how effective analysis and design principles can be used in a wide variety of applications and operating conditions. The book integrates the easy-to-use, hands-on XTurb design and analysis software that is available on a companion website for facilitating individual analyses and future studies. This component enhances the learning experience and helps with a deeper and more complete understanding of the subject matter. This important book: Covers aerodynamics, design and analysis and optimization of wind turbines Offers the author’s XTurb design and analysis software that is available on a companion website for individual analyses and future studies Includes unique chapters on blade element momentum theory, airfoil aerodynamics, rotational augmentation, vortex-wake methods, actuator-line modeling, and designing aerodynamically scaled turbines for model-scale experiments Demonstrates how design principles can be applied to a variety of applications and operating conditions Written for senior undergraduate and graduate students in wind energy as well as practicing engineers and scientists, Aerodynamics of Wind Turbines is an authoritative text that offers a guide to the fundamental principles, design and analysis of wind turbines.
Download or read book CFD for Wind and Tidal Offshore Turbines written by Esteban Ferrer and published by Springer. This book was released on 2015-06-09 with total page 134 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book encompasses novel CFD techniques to compute offshore wind and tidal applications. Computational fluid dynamics (CFD) techniques are regarded as the main design tool to explore the new engineering challenges presented by offshore wind and tidal turbines for energy generation. The difficulty and costs of undertaking experimental tests in offshore environments have increased the interest in the field of CFD which is used to design appropriate turbines and blades, understand fluid flow physical phenomena associated with offshore environments, predict power production or characterise offshore environments, amongst other topics.
