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Filename 6.2014-01711.pdf
filesize 1.87 MB
Version 1
Date added October 31, 2014
Downloaded 2348 times
Category Energy Security, Offshore Wind, Renewable Energy, Wind Energy
report-id SAND2013-4677A
author Daniele Ragni, Carlos Simao Ferreira, Matthew Barone
year 2013

The present study addresses the experimental and numerical veri cation of the performance
of a new airfoil design for lift driven vertical-axis wind-turbines (VAWT). The
airfoil is obtained by a genetic algorithm optimization of the objective function proposed by
Sim~ao Ferreira and Geurts [19], which optimizes the aerodynamic performance of airfoils
having a relatively larger thickness, providing with better structural sti ness compared
to more slender NACA design. The work presents an experimental analysis of such improved
performance of a 26% thick VAWT-optimized airfoil (DU12W262). The 2D
ow
velocity, pressure and aerodynamic loads are measured by combined use of Particle Image
Velocimetry, wall-pressure sensors and wake rakes. Additionally, the airfoil surface
pressure is determined by integrating the pressure equation from the experimental velocity
eld. Results are initially obtained with the airfoil in steady conditions, at Reynolds
3:5  105, 7:0  105 and 1:0  106 with both free and forced (1%c) boundary layer transition.
Xfoil simulations are employed for comparison to the experimental results, showing a good
agreement in the linear range of angle of attack and a consistent lift/drag overestimation
in the separated one. The experimental data are used as input for a numerical simulation
of a 2D VAWT. CFD simulations of the airfoil are performed and validated against the
experimental data. NOTE: This is a draft and incomplete version of the paper, as the CFD
simulations are yet not available. The full updated version of the paper will be available upon
the conference.