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Title: Horizontal Axis Wind Turbine Blade Aerodynamics in Experiments and Modeling

Abstract

No abstract prepared.

Authors:
;
Publication Date:
Research Org.:
National Renewable Energy Lab. (NREL), Golden, CO (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
907991
DOE Contract Number:
AC36-99-GO10337
Resource Type:
Journal Article
Resource Relation:
Journal Name: IEEE Transactions on Energy Conversion; Journal Volume: 22; Journal Issue: 1, March 2007
Country of Publication:
United States
Language:
English
Subject:
17 WIND ENERGY; AERODYNAMICS; SIMULATION; WIND TURBINES; TURBINE BLADES; WIND POWER; Wind Energy

Citation Formats

Schreck, S. J., and Robinson, M. C. Horizontal Axis Wind Turbine Blade Aerodynamics in Experiments and Modeling. United States: N. p., 2007. Web. doi:10.1109/TEC.2006.889620.
Schreck, S. J., & Robinson, M. C. Horizontal Axis Wind Turbine Blade Aerodynamics in Experiments and Modeling. United States. doi:10.1109/TEC.2006.889620.
Schreck, S. J., and Robinson, M. C. Thu . "Horizontal Axis Wind Turbine Blade Aerodynamics in Experiments and Modeling". United States. doi:10.1109/TEC.2006.889620.
@article{osti_907991,
title = {Horizontal Axis Wind Turbine Blade Aerodynamics in Experiments and Modeling},
author = {Schreck, S. J. and Robinson, M. C},
abstractNote = {No abstract prepared.},
doi = {10.1109/TEC.2006.889620},
journal = {IEEE Transactions on Energy Conversion},
number = 1, March 2007,
volume = 22,
place = {United States},
year = {Thu Mar 01 00:00:00 EST 2007},
month = {Thu Mar 01 00:00:00 EST 2007}
}
  • Most existing analyses of the blade loads on horizontal axis wind turbines are conducted using linear steady-state aerodynamics, but evaluation of loads resulting from wind turbulence or gusts may not be adequate using these techniques. This study develops single-parameter approximations for both the shed wake and trailing wake components of the unsteady aerodynamics and incorporates them into a code that evaluates mean and cyclic blade loading. The effect on loads due to the deterministic effects of wind shear and tower interference and the stochastic effects of wind turbulence are examined. The aeroelastic equations including degrees of freedom for blade flexingmore » and axial tower motion are solved in the time domain using turbulent wind input. Verification of the single-parameter models is by comparison to general analytic solutions and test data available in the literature. The model for shed wake is compared to exact solutions for translating airfoils and to two-dimensional approximations for rotary-wing effects. Two trailing wake models are evaluated using results from wind turbine tests and helicopter analysis. Comparison of loads predictions is made to Howden 330/26 Wind Turbine data showing good agreement for cyclic and mean loads. Results show that the largest contribution from unsteady aerodynamics is an increase in mean loads due to the induced velocity lag caused by the trailing wake.« less
  • Power augmentation and velocity measurements in the wake of a HAWT blade with Mie type tip vane (a tip device on the main blade) are presented. The maximum C{sub p} with a Mie type tip vane is found to be 15% larger than that without the Mie type tip vane. Power augmentation caused by the Mie type tip vane is mainly due to the reduction of tip vortex and the diffusing effect by the Mie type tip vane. The effects of a Mie type tip vane are quantitatively verified by the velocity distributions around the tip of the main blade.more » The velocity distribution was measured by three-dimensional hot wire probes, which measured the axial, radial, and tangential velocity components. The circulation distributions along the main blade with a Mie type tip vane and without a Mie type tip vane were obtained from the measured velocity distributions. A strong reduction of bound vorticity is found for the main blade tip without the Mie type tip vane, whereas the bound vorticity persists on the main blade tip with the Mie type tip vane.« less
  • The accurate prediction of horizontal axis, wind turbine cyclic blade loads is critical in the design of a machine that is fatigue life limited. A rotor code called LOADS has been developed that analyzes blade loads for rigid-hub rotors of simple geometry but includes blade flap-wise flexing and unsteady aerodynamics. The code is described and the results of its application to the SERI combined experiment tests using turbulent wind simulation are presented with some initial conclusions regarding the accuracy of the results.
  • Previous theoretical work has examined turbulence at a point rotating in a vertical plane, as in a horizontal-axis wind turbine (HAWT). The present paper extends the theoretical model to apply to the vertical-axis wind turbine (VAWT). The model's results, as simulated by computer, are compared with corresponding results obtained by analyzing field data, confirming the model's usefulness. Finally, suggestions are made for future applications of the model.
  • Surface pressure data from the National Renewable Energy Laboratory's ''Unsteady Aerodynamics Experiment'' were analyzed to characterize the impact of three-dimensionality, unsteadiness, and flow separation effects observed to occur on downwind horizontal axis wind turbines (HAWT). Surface pressure and strain gage data were collected from two rectangular planform blades with S809 airfoil cross-sections, one flat and one twisted. Both blades were characterized by the maximum leading edge suction pressure and by the azimuth, velocity, and yaw at which it occurred. The occurrence of dynamic stall at all but the inboard station (30% span) shows good quantitative agreement with the theoretical limitsmore » on inflow velocity and yaw that should yield dynamic stall events. A full three-dimensional characterization of the surface pressure topographies combined with flow visualization data from surface mounted tufts offer key insights into the three-dimensional processes involved in the unsteady separation process and may help to explain the discrepancies observed with force measurements at 30% span. The results suggest that quasi-static separation and dynamic stall analysis methods relying on purely two-dimensional flow characterizations may not be capable of simulating the complex three-dimensional flows observed with these data.« less