Blade Three-Dimensional Dynamic Stall Response to Wind Turbine Operating Condition

2005 ◽  
Vol 127 (4) ◽  
pp. 488-495 ◽  
Author(s):  
S. Schreck ◽  
M. Robinson
Keyword(s):  
Wind Turbine ◽  
Flexible Structures ◽  
Three Dimensional ◽  
Unsteady Aerodynamics ◽  
Dynamic Stall ◽  
Aerodynamic Load ◽  
Load Prediction ◽  
The Cost ◽  
Turbine Design ◽  
Yaw Angle

To further reduce the cost of wind energy, future turbine designs will continue to migrate toward lighter and more flexible structures. Thus, the accuracy and reliability of aerodynamic load prediction has become a primary consideration in turbine design codes. Dynamically stalled flows routinely generated during yawed operation are powerful and potentially destructive, as well as complex and difficult to model. As a prerequisite to aerodynamics model improvements, wind turbine dynamic stall must be characterized in detail and thoroughly understood. The current study analyzed turbine blade surface pressure data and local inflow data acquired by the NREL Unsteady Aerodynamics Experiment during the NASA Ames wind tunnel experiment. Analyses identified and characterized two key dynamic stall processes, vortex initiation and vortex convection, across a broad parameter range. Results showed that both initiation and convection exhibited pronounced three-dimensional kinematics, which responded in systematic fashion to variations in wind speed, turbine yaw angle, and radial location.

Blade Three-Dimensional Dynamic Stall Response to Wind Turbine Operating Condition

2003 ◽  
Author(s):  
S. Schreck ◽  
M. Robinson
Keyword(s):  
Wind Turbine ◽  
Flexible Structures ◽  
Three Dimensional ◽  
Unsteady Aerodynamics ◽  
Dynamic Stall ◽  
Aerodynamic Load ◽  
Load Prediction ◽  
The Cost ◽  
Turbine Design ◽  
Yaw Angle

To further reduce the cost of wind energy, future turbine designs will continue to migrate toward lighter and more flexible structures. Thus, the accuracy and reliability of aerodynamic load prediction has become a primary consideration in turbine design codes. Dynamically stalled flows routinely generated during yawed operation are powerful and potentially destructive, as well as complex and difficult to model. As a prerequisite to aerodynamics model improvements, wind turbine dynamic stall must be characterized in detail and thoroughly understood. In the current study, turbine blade surface pressure data and local inflow data acquired by the NREL Unsteady Aerodynamics Experiment during the NASA Ames wind tunnel experiment were analyzed. The dynamically stalled, vortex dominated flow field responded in systematic fashion to variations in wind speed, turbine yaw angle, and radial location, forming the basis for more thorough comprehension of wind turbine dynamic stall and improved modeling.

scholarly journals Wind Turbine Blade Flow Fields and Prospects for Active Aerodynamic Control

2007 ◽  
Author(s):  
S. Schreck ◽  
M. Robinson
Keyword(s):  
Wind Turbine ◽  
Three Dimensional ◽  
Flow Fields ◽  
Operating Conditions ◽  
Dynamic Stall ◽  
Aerodynamic Load ◽  
Aerodynamic Loads ◽  
Aerodynamic Loading ◽  
Technical Community ◽  
Aerodynamic Control

As wind turbines continue to grow larger, problems associated with adverse aerodynamic loads will grow more critical. Thus, the wind energy technical community has begun to seriously consider the potential of aerodynamic control methodologies for mitigating adverse aerodynamic loading. Spatial and temporal attributes of the structures and processes present in these flow fields hold important implications for active aerodynamic control methodologies currently being contemplated for wind turbine applications. The current work uses complementary experimental and computational methodologies, to isolate and characterize key attributes of blade flow fields associated with axisymmetric and yawed turbine operation. During axisymmetric operation, a highly three-dimensional, shear layer dominated flow field yields rotational augmentation of both mean and standard deviation levels of aerodynamic forces. Under yawed operating conditions, pseudo-sinusoidal inflow angle oscillations elicit dynamic stall, which significantly intensifies aerodynamic load production. Both rotationally augmented and dynamically stalled flows possess attributes likely to pose central challenges for turbine flow control. Whether active control of turbine aerodynamics can help alleviate adverse aerodynamic loads will depend on comprehension and command of the issues documented herein.

scholarly journals THE PATH FROM FUNCTIONAL TO DETAILED DESIGN OF A CONING ROTOR WIND TURBINE CONCEPT

2011 ◽  
Author(s):  
Curran A. Crawford
Keyword(s):  
Wind Energy ◽  
Wind Turbine ◽  
Detailed Analysis ◽  
Theoretical Basis ◽  
Design Theory ◽  
Functional Design ◽  
Detailed Design ◽  
Definition Of ◽  
The Cost ◽  
Turbine Design

This paper provides a brief overview of functional design theory, which is then used to examine choices in wind turbine design. Definition of function is used to examine fundamental design choices in engineering a machine to capture energy from the wind. Specifically, rationalization is presented for a coning rotor wind turbine concept, potentially able to greatly reduce the cost of wind energy. The work presented here has provided a theoretical basis in design theory to motivate the development of specialized analysis tools and more detailed analysis of the concept.

Computation of Hoisting Forces on Wind Turbine Blades Using Computation Fluid Dynamics

2013 ◽  
Vol 446-447 ◽  
pp. 452-457 ◽  
Author(s):  
Yong Wang ◽  
De Tian ◽  
Wei He
Keyword(s):  
Fluid Dynamics ◽  
Wind Turbine ◽  
Pitch Angle ◽  
Turbine Blades ◽  
Three Dimensional ◽  
Azimuth Angle ◽  
Wind Turbine Blades ◽  
Mesh Model ◽  
Cfd Method ◽  
Yaw Angle

The hoisting forces on a 38.5m wind turbine blade in multiple positions are computed using the computational fluid dynamics (CFD) method. The computation model is constructed with the steady wind conditions, blade mesh model and the blade positions which are determined by the blade pitch angle, azimuth angle and rotor yaw angle. The maximal and minimal hoisting forces in three-dimensional coordinates are found and the corresponding pitch angle, azimuth angle and yaw angle are obtained. The change of the hoisting forces on wind turbine blades is analyzed. Suggestions are given to decrease the hoisting forces of the blade in open wind environment.

New Insight Into the Flow Around a Wind Turbine Airfoil Section1

2005 ◽  
Vol 127 (2) ◽  
pp. 214-222 ◽  
Author(s):  
F. Bertagnolio ◽  
N. N. Sørensen ◽  
F. Rasmussen
Keyword(s):  
Wind Turbine ◽  
Numerical Models ◽  
Turbine Blades ◽  
Three Dimensional ◽  
Unsteady Aerodynamics ◽  
Turbulence Models ◽  
Navier Stokes ◽  
Detached Eddy Simulation ◽  
Pitching Airfoil ◽  
Wind Turbine Airfoil

The objective of this paper is an improved understanding of the physics of the aeroelastic motion of wind turbine blades in order to improve the numerical models used for their design. Two- and three-dimensional Navier–Stokes calculations of the flow around a wind turbine airfoil using the k−ω SST and Detached Eddy Simulation (DES) turbulence models, as well as an engineering semiempirical dynamic stall model, are conducted. The computational results are compared to the experimental results that are available for both the static airfoil and the pitching airfoil. It is shown that the Navier–Stokes simulations can reproduce the main characteristic features of the flow. The DES model seems to be able to reproduce most of the details of the unsteady aerodynamics. Aerodynamic work computations indicate that a plunging motion of the airfoil can become unstable.

scholarly journals Active Aerodynamic Load Control for Improved Wind Turbine Design

2020 ◽  
Vol 1618 ◽  
pp. 052079
Author(s):  
D. Todd Griffith ◽  
Neal E. Fine ◽  
John A. Cooney ◽  
Mario A. Rotea ◽  
G. Valerio Iungo
Keyword(s):  
Wind Turbine ◽  
Load Control ◽  
Aerodynamic Load ◽  
Turbine Design

Wake and Performance Predictions of Two- and Three-Bladed Wind Turbines Based on the Actuator Line Model1

2021 ◽  
Vol 143 (5) ◽  
Author(s):  
Sebastian Henao Garcia ◽  
Aldo Benavides-Morán ◽  
Omar D. Lopez Mejia
Keyword(s):  
Wind Turbine ◽  
Three Dimensional ◽  
Operating Conditions ◽  
Navier Stokes ◽  
Speed Ratio ◽  
Power Extraction ◽  
Low Incidence ◽  
And Performance ◽  
Turbine Design ◽  
Simulation Parameters

Abstract This paper challenges the standard wind turbine design numerically assessing the wake and aerodynamic performance of two- and three-bladed wind turbine models implementing downwind and upwind rotor configurations, respectively. The simulations are conducted using the actuator line model (ALM) coupled with a three-dimensional Navier Stokes solver implementing the k−ω shear stress transport turbulence model. The sensitivity of the ALM to multiple simulation parameters is analyzed in detail and numerical results are compared against experimental data. These analyses highlight the most suitable Gaussian radius at the rotor to be equal to twice the chord length at 95% of the blade for a tip-speed ratio (TSR) of ten, while the Gaussian radius at the tower and the number of actuator points have a low incidence on the flow field computations overall. The numerical axial velocity profiles show better agreement upstream than downstream the rotor, while the discrepancies are not consistent through all the assessed operating conditions, thus highlighting that the ALM parameters are also dependent on the wind turbine's operating conditions rather than being merely geometric parameters. Particularly, for the upwind three-bladed wind turbine model, the accuracy of the total thrust computations improves as the TSR increases, while the least accurate wake predictions are found for its design TSR. Finally, when comparing both turbine models, an accurate representation of the downwind configuration is observed as well as realistic power extraction estimates. Indeed, the results confirm that rotors with fewer blades are more suitable to operate at high TSRs.

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.

Study on dual peg-in-hole insertion using of constraints formed in the environment

2017 ◽  
Vol 44 (6) ◽  
pp. 730-740 ◽  
Author(s):  
Jianhua Su ◽  
Rui Li ◽  
Hong Qiao ◽  
Jing Xu ◽  
Qinglin Ai ◽  
...  
Keyword(s):  
Configuration Space ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Force Sensor ◽  
High Dimensional ◽  
Content Type ◽  
Attractive Region ◽  
Low Dimensional ◽  
The Cost ◽  
Yaw Angle

Purpose The purpose of this paper is to develop a dual peg-in-hole insertion strategy. Dual peg-in-hole insertion is the most common task in manufacturing. Most of the previous work develop the insertion strategy in a two- or three-dimensional space, in which they suppose the initial yaw angle is zero and only concern the roll and pitch angles. However, in some case, the yaw angle could not be ignored due to the pose uncertainty of the peg on the gripper. Therefore, there is a need to design the insertion strategy in a higher-dimensional configuration space. Design/methodology/approach In this paper, the authors handle the insertion problem by converting it into several sub-problems based on the attractive region formed by the constraints. The existence of the attractive region in the high-dimensional configuration space is first discussed. Then, the construction of the high-dimensional attractive region with its sub-attractive region in the low-dimensional space is proposed. Therefore, the robotic insertion strategy can be designed in the subspace to eliminate some uncertainties between the dual pegs and dual holes. Findings Dual peg-in-hole insertion is realized without using of force sensors. The proposed strategy is also used to demonstrate the precision dual peg-in-hole insertion, where the clearance between the dual-peg and dual-hole is about 0.02 mm. Practical implications The sensor-less insertion strategy will not increase the cost of the assembly system and also can be used in the dual peg-in-hole insertion. Originality/value The theoretical and experimental analyses for dual peg-in-hole insertion are proposed without using of force sensor.

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