Prediction of Wind Turbine Rotor Loads Using the Beddoes-Leishman Model for Dynamic Stall

1995 ◽  
Vol 117 (3) ◽  
pp. 200-204 ◽  
Author(s):  
K. Pierce ◽  
A. C. Hansen
Keyword(s):  
Wind Turbines ◽  
Aerodynamic Force ◽  
Unsteady Aerodynamics ◽  
Turbine Rotor ◽  
Dynamic Stall ◽  
University Of Utah ◽  
Horizontal Axis Wind Turbines ◽  
Wind Tunnel Data ◽  
The University ◽  
Wind Turbine Rotor

The Beddoes-Leishman model for unsteady aerodynamics and dynamic stall has recently been implemented in YawDyn, a rotor analysis code developed at the University of Utah for the study of yaw loads and motions of horizontal axis wind turbines. This paper presents results obtained from validation efforts for the Beddoes model. Comparisons of predicted aerodynamic force coefficients with wind tunnel data and data from the combined experiment rotor are presented. Also, yaw motion comparisons with the combined experiment rotor are presented. In general the comparisons with the measured data are good, indicating that the model is appropriate for the conditions encountered by wind turbines.

Extensive Validation of HAWT Unsteady Modelling Using BEM and CFD

2020 ◽  
Author(s):  
Raffaele Peraro ◽  
Luca Menegozzo ◽  
Andrea Dal Monte ◽  
Ernesto Benini
Keyword(s):  
Wind Turbines ◽  
Three Dimensional ◽  
Unsteady Aerodynamics ◽  
Dynamic Stall ◽  
Flow Conditions ◽  
Machine Performance ◽  
Horizontal Axis Wind Turbines ◽  
Computational Fluid Dynamics Cfd ◽  
Nrel Phase Vi ◽  
Blade Element

Abstract The present work aims to present two different approaches to model the unsteady aerodynamics of horizontal-axis wind turbines (HAWTs). A complete and extensive comparison has been established between the results obtained using a low-fidelity calculation tool, as the Blade Element Momentum (BEM), and a high-fidelity technique, as the Computational Fluid Dynamics (CFD). Regarding the first calculation strategy, an accurate revision in polar diagrams calculation and the implementation of yaw and dynamic stall routines have endowed the BEM code to predict the machine performance under unsteady flow conditions. In order to achieve an accurate validation, the proposed BEM solver has been tested on AOC 15/50 and NREL Phase VI wind turbines. Referring to CFD techniques, a three-dimensional unsteady model has been improved to study the aerodynamic behaviour of the machine in case of yawed incoming wind.

Development of a Wind Tunnel Test Apparatus for Horizontal Axis Wind Turbine Rotor Testing

2008 ◽  
Author(s):  
Michael McWillam ◽  
David Johnson
Keyword(s):  
Wind Tunnel ◽  
Wind Turbine ◽  
Wind Turbines ◽  
High Speed ◽  
Turbine Rotor ◽  
Dynamic Stall ◽  
Flow Structures ◽  
Horizontal Axis Wind Turbine ◽  
Wind Turbine Rotor ◽  
Blade Geometry

The engineering of wind turbines is not fully mature. There are still phenomena, particularly dynamic stall that cannot be accurately modeled. Dynamic stall contributes to fatigue stress and premature failure in many turbine components. The three dimensionality of dynamic stall make these structures unique for wind turbines. Currently flow visualization of dynamic stall on a wind turbine rotor has not been achieved, but these visualizations can reveal a great deal about the structures that contribute to dynamic stall. Particle Image Velocimetry (PIV) is a powerful experimental technique that can take non-intrusive flow measurements of planar flow simultaneously. High-speed cameras enable time resolved PIV can reveal the transient development. This technique is suited to gain a better understanding of dynamic stall. A custom 3.27 m diameter wind turbine has been built to allow such measurements on the blade. The camera is mounted on the hub and will take measurements within the rotating domain. Mirrors are used so that laser illumination rotates with the blade. The wind turbine will operate in controlled conditions provided by a large wind tunnel. High-speed pressure data acquisition will be used in conjunction with PIV to get an understanding of the forces associated with the flow structures. Many experiments will be made possible by this apparatus. First the flow structures responsible for the forces can be identified. Quantitative measurements of the flow field will identify the development of the stall vortex. The quantified flow structures can be used to verify and improve models. The spatial resolution of PIV can map the three dimensional structure in great detail. The experimental apparatus is independent of the blade geometry; as such multiple blades can be used to identify the effect of blade geometry. Finally flow control research in the field of aviation can be applied to control dynamic stall. These experiments will be subject of much of the future work at the University of Waterloo. Potentially this work will unlock the secrets of dynamic stall and improve the integrity of wind turbines.

Development and Application of a Simulation Tool for Vertical and Horizontal Axis Wind Turbines

2013 ◽  
Author(s):  
David Marten ◽  
Juliane Wendler ◽  
Georgios Pechlivanoglou ◽  
Christian Navid Nayeri ◽  
Christian Oliver Paschereit
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Vertical Axis ◽  
Turbine Rotor ◽  
Horizontal Axis ◽  
Vertical Axis Wind Turbine ◽  
First Case ◽  
Horizontal Axis Wind Turbines ◽  
Lift And Drag ◽  
The Impact

A double-multiple-streamtube vertical axis wind turbine simulation and design module has been integrated within the open-source wind turbine simulator QBlade. QBlade also contains the XFOIL airfoil analysis functionalities, which makes the software a single tool that comprises all functionality needed for the design and simulation of vertical or horizontal axis wind turbines. The functionality includes two dimensional airfoil design and analysis, lift and drag polar extrapolation, rotor blade design and wind turbine performance simulation. The QBlade software also inherits a generator module, pitch and rotational speed controllers, geometry export functionality and the simulation of rotor characteristics maps. Besides that, QBlade serves as a tool to compare different blade designs and their performance and to thoroughly investigate the distribution of all relevant variables along the rotor in an included post processor. The benefits of this code will be illustrated with two different case studies. The first case deals with the effect of stall delaying vortex generators on a vertical axis wind turbine rotor. The second case outlines the impact of helical blades and blade number on the time varying loads of a vertical axis wind turbine.

Design and Evaluation of a Rooftop Wind Turbine Rotor With Untwisted Blades

2013 ◽  
Author(s):  
Sayem Zafar ◽  
Mohamed Gadalla
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Low Cost ◽  
Turbine Blades ◽  
Angle Of Attack ◽  
Turbine Rotor ◽  
Wind Turbine Blades ◽  
Wind Speeds ◽  
Small Wind Turbines ◽  
Wind Turbine Rotor

A small horizontal axis wind turbine rotor was designed and tested with aerodynamically efficient, economical and easy to manufacture blades. Basic blade aerodynamic analysis was conducted using commercially available software. The blade span was constrained such that the complete wind turbine can be rooftop mountable with the envisioned wind turbine height of around 8 m. The blade was designed without any taper or twist to comply with the low cost and ease of manufacturing requirements. The aerodynamic analysis suggested laminar flow airfoils to be the most efficient airfoils for such use. Using NACA 63-418 airfoil, a rectangular blade geometry was selected with chord length of 0.27[m] and span of 1.52[m]. Glass reinforced plastic was used as the blade material for low cost and favorable strength to weight ratio with a skin thickness of 1[mm]. Because of the resultant velocity changes with respect to the blade span, while the blade is rotating, an optimal installed angle of attack was to be determined. The installed angle of attack was required to produce the highest possible rotation under usual wind speeds while start at relatively low speed. Tests were conducted at multiple wind speeds with blades mounted on free rotating shaft. The turbine was tested for three different installed angles and rotational speeds were recorded. The result showed increase in rotational speed with the increase in blade angle away from the free-stream velocity direction while the start-up speeds were found to be within close range of each other. At the optimal angle was found to be 22° from the plane of rotation. The results seem very promising for a low cost small wind turbine with no twist and taper in the blade. The tests established that non-twisted wind turbine blades, when used for rooftop small wind turbines, can generate useable electrical power for domestic consumption. It also established that, for small wind turbines, non-twisted, non-tapered blades provide an economical yet productive alternative to the existing complex wind turbine blades.

Challenges in Modeling the Unsteady Aerodynamics of Wind Turbines

2002 ◽  
Author(s):  
J. Gordon Leishman
Keyword(s):  
Velocity Field ◽  
Wind Turbines ◽  
Unsteady Aerodynamics ◽  
Dynamic Stall ◽  
Experimental Measurements ◽  
Fundamental Limits ◽  
Unsteady Aerodynamic ◽  
Modeling Techniques ◽  
Induced Velocity

Many of the aerodynamic phenomena contributing to the observed effects on wind turbines are now known, but the details of the flow are still poorly understood and are challenging to predict accurately, issues discussed herein include the modeling of the induced velocity field produced by the vortical wake behind the turbine, the various unsteady aerodynamic issues associated with the blade sections, and the intricacies of dynamic stall. Fundamental limits exist in the capabilities of all models, and misunderstandings or ambiguities can also arise in how these models should be properly applied. A challenge for analysts is to use complementary experimental measurements and modeling techniques to better understand the aerodynamic problems found on wind turbines, and to develop more rigorous models with wider ranges of application.

scholarly journals An Innovative Correction Method of Wind Speed for Efficiency Evaluation of Wind Turbines

ACTA IMEKO ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 46
Author(s):  
Alessio Carullo ◽  
Alessandro Ciocia ◽  
Gabriele Malgaroli ◽  
Filippo Spertino
Keyword(s):  
Wind Speed ◽  
Wind Turbines ◽  
Wind Farm ◽  
Southern Italy ◽  
Wind Farms ◽  
Correction Method ◽  
Turbine Rotor ◽  
Meteorological Station ◽  
Efficiency Evaluation ◽  
Horizontal Axis Wind Turbines

The performance of horizontal axis Wind Turbines (WTs) is strongly affected by the wind speed entering in their rotor. Generally, this quantity is not available, because the wind speed is measured on the nacelle behind the turbine rotor, providing a lower value. Therefore, two correction methods are usually employed, requiring two input quantities: the wind speed on the back of the turbine nacelle and the wind speed measured by a meteorological mast close to the turbines under analysis. However, the presence of this station in wind farms is rare and the number of WTs in the wind farm is high. This paper proposes an innovative correction, named “Statistical Method” (SM), that evaluates the efficiency of WTs by estimating the wind speed entering in the WTs rotor. This method relies on the manufacturer power curve and the data measured by the WT anemometer only, thus having the possibility to be also applied in wind farms without a meteorological station. The effectiveness of such a method is discussed by comparing the results obtained by the standard methods implemented on two turbines (rated power = 1.5 MW and 2.5 MW) of a wind power plant (nominal power = 80 MW) in Southern Italy.

Strategic Blade Shape Optimization for Aerodynamic Performance Improvement of Wind Turbines

2016 ◽  
Author(s):  
Youjin Kim ◽  
Ali Al-Abadi ◽  
Antonio Delgado
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Optimization Methods ◽  
Turbine Rotor ◽  
Aerodynamic Performance ◽  
Power Coefficient ◽  
Speed Ratio ◽  
Blade Shape ◽  
Improved Design ◽  
Wind Turbine Rotor

This study introduces strategic methods for improving the aerodynamic performance of wind turbines. It was completed by combining different optimization methods for each part of the wind turbine rotor. The chord length and pitch angle are optimized by a torque-matched method (TMASO), whereas the airfoil shape is optimized by the genetic algorithm (GA). The TMASO is implemented to produce an improved design of a reference turbine (NREL UAE Phase V). The GA is operated to generate a novel airfoil design that is evaluated by automatic interfacing for the highest gliding ratio (GR). The adopted method produces an optimized wind turbine with an 11% increase of power coefficient (Cp) with 30% less of the corresponding tip speed ratio (TSR). Furthermore, the optimized wind turbine shows reduced tip loss effect.

scholarly journals Flight Altitudes of Raptors in Southern Africa Highlight Vulnerability of Threatened Species to Wind Turbines

2021 ◽  
Vol 9 ◽  
Author(s):  
Christopher J. W. McClure ◽  
Leah Dunn ◽  
Jennifer D. McCabe ◽  
Brian W. Rolek ◽  
André Botha ◽  
...  
Keyword(s):  
Wind Energy ◽  
Wind Power ◽  
Wind Turbines ◽  
Southern Africa ◽  
Threatened Species ◽  
Turbine Rotor ◽  
Energy Infrastructure ◽  
Negative Impacts ◽  
Wind Power Development ◽  
Wind Turbine Rotor

Energy infrastructure, particularly for wind power, is rapidly expanding in Africa, creating the potential for conflict with at-risk wildlife populations. Raptor populations are especially susceptible to negative impacts of fatalities from wind energy because individuals tend to be long-lived and reproduce slowly. A major determinant of risk of collision between flying birds and wind turbines is the altitude above ground at which a bird flies. We examine 18,710 observations of flying raptors recorded in southern Africa and we evaluate, for 49 species, the frequency with which they were observed to fly at the general height of a wind turbine rotor-swept zone (50–150 m). Threatened species, especially vultures, were more likely to be observed at turbine height than were other species, suggesting that these raptors are most likely to be affected by wind power development across southern Africa. Our results highlight that threatened raptor species, particularly vultures, might be especially impacted by expanded wind energy infrastructure across southern Africa.

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