Rotational Augmentation of Horizontal Axis Wind Turbine Blade Aerodynamic Response

2002 ◽  
Author(s):  
S. Schreck ◽  
M. Robinson
Keyword(s):  
Wind Turbine ◽  
Surface Pressure ◽  
Unsteady Aerodynamics ◽  
Horizontal Axis ◽  
Pressure Data ◽  
Aerodynamic Forces ◽  
Horizontal Axis Wind Turbine ◽  
Pressure Distributions ◽  
Rotating Blade ◽  
Wind Tunnel Data

Surface pressure data were acquired using the NREL Unsteady Aerodynamics Experiment, a full-scale horizontal axis wind turbine, which was erected in the NASA Ames 80 ft × 120 ft wind tunnel. Data were collected first for a stationary blade, and then for a rotating blade with the turbine disk at zero yaw. Analyses compared aerodynamic forces and surface pressure distributions under rotating conditions against analogous baseline data acquired from the stationary blade. This comparison allowed rotational modifications to blade aerodynamics to be characterized in detail. Rotating conditions were seen to dramatically amplify aerodynamic forces, and radically alter surface pressure distributions. These and subsequent findings will more fully reveal the structures and interactions responsible for these flow field enhancements, and help establish the basis for formalizing comprehension in physics based models.

Boundary Layer State and Flow Field Structure Underlying Rotational Augmentation of Blade Aerodynamic Response

2003 ◽  
Vol 125 (4) ◽  
pp. 448-456 ◽  
Author(s):  
S. Schreck ◽  
M. Robinson
Keyword(s):  
Boundary Layer ◽  
Surface Pressure ◽  
Normal Force ◽  
Unsteady Aerodynamics ◽  
Boundary Layer Separation ◽  
Pressure Data ◽  
Horizontal Axis Wind Turbine ◽  
Pressure Distributions ◽  
Standard Deviations ◽  
Tunnel Time

Blade rotation routinely and significantly augments aerodynamic forces during zero yaw horizontal axis wind turbine (HAWT) operation. To better understand the flow physics underlying this phenomenon, time dependent blade surface pressure data were acquired from the National Renewable Energy Laboratory (NREL). Unsteady Aerodynamics Experiment (UAE), a full-scale HAWT tested in the NASA Ames 80-by-120-foot wind tunnel. Time records of surface pressures and normal force were processed to obtain means and standard deviations. Surface pressure means and standard deviations were analyzed to identify boundary layer separation and shear layer impingement locations. Separation and impingement kinematics were then correlated with normal force behavior. Results showed that rotational augmentation was linked to specific separation and impingement behaviors, and to associated three-dimensionality in surface pressure distributions.

Surface Pressure Distribution on a Blade of a 10 m Diameter HAWT (Field Measurements versus Wind Tunnel Measurements)

2005 ◽  
Vol 127 (2) ◽  
pp. 185-191 ◽  
Author(s):  
T. Maeda ◽  
E. Ismaili ◽  
H. Kawabuchi ◽  
Y. Kamada
Keyword(s):  
Wind Tunnel ◽  
Surface Pressure ◽  
Field Measurements ◽  
Reynolds Numbers ◽  
Blade Surface ◽  
Pressure Data ◽  
Surface Pressure Distribution ◽  
Pressure Distributions ◽  
Wind Tunnel Data ◽  
Local Angle

This paper exploits blade surface pressure data acquired by testing a three-bladed upwind turbine operating in the field. Data were collected for a rotor blade at spanwise 0.7R with the rotor disc at zero yaw. Then, for the same blade, surface pressure data were acquired by testing in a wind tunnel. Analyses compared aerodynamic forces and surface pressure distributions under field conditions against analogous baseline data acquired from the wind tunnel data. The results show that aerodynamic performance of the section 70%, for local angle of attack below static stall, is similar for free stream and wind tunnel conditions and resemblances those commonly observed on two-dimensional aerofoils near stall. For post-stall flow, it is presumed that the exhibited differences are attributes of the differences on the Reynolds numbers at which the experiments were conducted.

Analysis of Unsteady Flows Past Horizontal Axis Wind Turbine Airfoils Based on Harmonic Balance Compressible Navier-Stokes Equations With Low-Speed Preconditioning

2011 ◽  
Author(s):  
M. Sergio Campobasso ◽  
Mohammad H. Baba-Ahmadi
Keyword(s):  
Wind Turbine ◽  
Time Domain ◽  
Harmonic Balance ◽  
Stokes Equations ◽  
Unsteady Aerodynamics ◽  
Horizontal Axis ◽  
Navier Stokes ◽  
Horizontal Axis Wind Turbine ◽  
Low Speed ◽  
Computational Performance

This paper presents the numerical models underlying the implementation of a novel harmonic balance compressible Navier-Stokes solver with low-speed preconditioning for wind turbine unsteady aerodynamics. The numerical integration of the harmonic balance equations is based on a multigrid iteration, and, for the first time, a numerical instability associated with the use of such an explicit approach in this context is discussed and resolved. The harmonic balance solver with low-speed preconditioning is well suited for the analyses of several unsteady periodic low-speed flows, such as those encountered in horizontal axis wind turbines. The computational performance and the accuracy of the technology being developed are assessed by computing the flow field past two sections of a wind turbine blade in yawed wind with both the time- and frequency-domain solvers. Results highlight that the harmonic balance solver can compute these periodic flows more than 10 times faster than its time-domain counterpart, and with an accuracy comparable to that of the time-domain solver.

Measurement of Unsteady Aerodynamics Load on the Blade of Field Horizontal Axis Wind Turbine

2007 ◽  
Author(s):  
Takao Maeda ◽  
Yasunari Kamada ◽  
Keita Naito ◽  
Yuu Ouchi ◽  
Masayoshi Kozawa
Keyword(s):  
Wind Turbine ◽  
Pressure Distribution ◽  
Mode Frequency ◽  
Horizontal Axis ◽  
Strain Gauges ◽  
Aerodynamic Forces ◽  
Horizontal Axis Wind Turbine ◽  
Blade Root ◽  
Blade Section ◽  
Mechanical Moment

This paper describes an experimental field study of the rotor aerodynamics of wind turbines. The test wind turbine is a horizontal axis wind turbine, or: HAWT with a diameter of 10m. The pressure distributions on the rotating blade are measured with multi point pressure transducers. Sectional aerodynamic forces are analyzed from pressure distribution. Blade root moments are measured simultaneously by a pair of strain gauges. The inflow wind is measured by a three component sonic anemometer, the local inflow of the blade section are measured by a pair of 7 hole Pitot tubes. The relation between the aerodynamic moments on the blade root from pressure distribution and the mechanical moment from strain gauges is discussed. The aerodynamic moments are estimated from the sectional aerodynamic forces and show oscillation caused by local wind speed and direction change. The mechanical moment shows similar oscillation to the aerodynamic excepting the short period oscillation of the blade first mode frequency. The fluctuation of the sectional aerodynamic force triggers resonant blade oscillations. Where stall is present along the blade section, the blade’s first mode frequency is dominant. Without stall, the rotating frequency is dominant in the blade root moment.

scholarly journals Analysis of Unsteady Flows Past Horizontal Axis Wind Turbine Airfoils Based on Harmonic Balance Compressible Navier-Stokes Equations With Low-Speed Preconditioning

2012 ◽  
Vol 134 (6) ◽  
Author(s):  
M. Sergio Campobasso ◽  
Mohammad H. Baba-Ahmadi
Keyword(s):  
Wind Turbine ◽  
Time Domain ◽  
Harmonic Balance ◽  
Stokes Equations ◽  
Unsteady Aerodynamics ◽  
Horizontal Axis ◽  
Navier Stokes ◽  
Horizontal Axis Wind Turbine ◽  
Low Speed ◽  
Computational Performance

This paper presents the numerical models underlying the implementation of a novel harmonic balance compressible Navier-Stokes solver with low-speed preconditioning for wind turbine unsteady aerodynamics. The numerical integration of the harmonic balance equations is based on a multigrid iteration, and, for the first time, a numerical instability associated with the use of such an explicit approach in this context is discussed and resolved. The harmonic balance solver with low-speed preconditioning is well suited for the analyses of several unsteady periodic low-speed flows, such as those encountered in horizontal axis wind turbines. The computational performance and the accuracy of the technology being developed are assessed by computing the flow field past two sections of a wind turbine blade in yawed wind with both the time-and frequency-domain solvers. Results highlight that the harmonic balance solver can compute these periodic flows more than 10 times faster than its time-domain counterpart, and with an accuracy comparable to that of the time-domain solver.

scholarly journals Icing distribution of rotating blade of horizontal axis wind turbine based on Quasi-3D numerical simulation

2018 ◽  
Vol 22 (Suppl. 2) ◽  
pp. 681-691 ◽  
Author(s):  
Yan Li ◽  
Shaolong Wang ◽  
Ce Sun ◽  
Xian Yi ◽  
Wenfeng Guo ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Wind Turbine ◽  
Turbine Blades ◽  
Liquid Water Content ◽  
Horizontal Axis ◽  
Drop Diameter ◽  
Wind Turbine Blades ◽  
Horizontal Axis Wind Turbine ◽  
Rotating Blade ◽  
Temperature Liquid

For researching on the rules of icing distribution on rotating blade of horizontal axis wind turbine, a Quasi-3-D method is proposed to research on icing on rotating blades of horizontal axis wind turbine by numerical simulation. A 2-D and 3-D method of evaluating the irregular shape of ice has been established. The model of rotating blade from a 1.5 MW horizontal axis wind turbine is used to simulate the process and shape of icing on blade. The simulation is carried out under the conditions with four important parameters including ambient temperature, liquid water content, medium volume drop diameter, and icing time. The results reveal that icing mainly happens on 50% ~ 70% of the blade surface along wingspan from tip to root of blade. There are two kinds of icing shapes including horn shape icing and streamline shape icing. The study can provide theoretical basis and numerical reference to development of anti and deicing strategy for wind turbine blades.

STRESS ANALYSIS PADA HORIZONTAL AXIS WIND TURBINE BLADE

POROS ◽  
2017 ◽  
Vol 12 (1) ◽  
pp. 41
Author(s):  
Achmad Rachmad Tullah ◽  
Made K Dhiputra ◽  
G Soeharsono
Keyword(s):  
Power Plant ◽  
Wind Turbine ◽  
Stress Analysis ◽  
Turbine Blade ◽  
Maximum Stress ◽  
Wind Turbine Blade ◽  
Horizontal Axis ◽  
Centrifugal Forces ◽  
Aerodynamic Forces ◽  
Horizontal Axis Wind Turbine

Abstract: Nowadays wind turbine is used widely in many countries as power plant. When the wind turbine blade rotates there will be aerodynamic forces acting on the blade such as drag, lift, weight and centrifugal forces. When designing wind turbine blade it is necessary to test whether the blade can withstand the aerodynamic forces or not. Stress analysis is a feature that can predict stress acting on construction. Nowadays there are many stress analysis softwares that can be used to predict stress. In this research the stress analysis will be used by using autodesk inventor.The research purposes are to find the stress acting on the wind turbine blade and to get the maximum stress location. 

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