Vortex generators (VGs) are commonly used for trimming the aerodynamic and aeroelastic performance of wind turbine blades by delaying flow separation. There is therefore a need for the development of reliable, still computationally affordable, models for blade designers to use to predict and enhance the aerodynamic characteristics of airfoils equipped with VGs. Such a model is proposed in the present paper, addressing in particular near-stall and post-stall airfoil performance. Starting from the three-dimensional Navier–Stokes equations that essentially describe the complex flow around a blade/VG configuration, a spanwise averaging procedure is applied, resulting in an equivalent set of two-dimensional equations, enriched with extra source terms. These terms are modelled using elementary vortex flow theory. In turbulent flows, the production term of the turbulent kinetic energy is also augmented by the vorticity induced by the VG. The model is evaluated by studying the flow past a blade section with and without VGs. An analysis of the performance of nine alternative VG configurations is also presented to demonstrate the sensitivity of the airfoil polars to the VG geometric parameters.

Keywords:
wind turbines, blades, vortices, turbulence, Navier-Stokes equations
Topics:
Airfoils, Flow (Dynamics), Generators, Turbulence, Vortices, Modeling
1.
Timmer
,
W. A.
, and
van Rooij
,
R. P. J. O. M.
,
2003
, “
Summary of the Delft University Wind Turbine Dedicated Airfoils
,”
ASME J. Sol. Energy Eng.
,
125
(
4
), pp.
488
–
496
.
2.
Jones, J. P., 1957, “The Calculation of the Paths of Vortices from a System of Vortex Generators and Comparison with Experiment,” Aeronautical Research Council, C. P. 361.
3.
Nickelson, J. D., 1986, “A Study of Vortex Generators at Low Reynolds Numbers,” Proc. AIAA 24th Aerospace Sciences Meeting, Reno Nevada.
4.
Wendt, B. J., and Reichert, B. A., 1996, “The Modelling of Symmetric Airfoil Vortex Generators,” AIAA Paper No. 96-0807.
5.
Kunik, W. G., 1986, “Application of a Computational Model for Vortex Generators in Subsonic Internal Flow,” AIAA Paper No. 86-1458.
6.
Chang, P. K., 1987, “Computation of the Turbulent Boundary Layer Downstream of Vortex Generators,” Technical Report No. DTRC-87/054, David Taylor Research Center.
7.
Cho, S. Y., and Greber, I., 1994, “Three-Dimensional Compressible Turbulent Flow Computations for a Diffusing S-Duct With/Without Vortex Generators,” Technical Report No. NASA CR-195390, Lewis Research Center.
8.
Fuglsang, P., Antoniou, I., Dahl, K. S., and Madsen, H. Aa., 1998, “Wind Tunnel Tests of the FFA-W3-241, FFA-W3-301 and NACA 63–430 Airfoils,” Technical Report No Risø-R-1041(EN), Risø National Laboratory, Roskilde, Denmark.
9.
Bak, C., Fuglsang, P., Mac Gaunaa, Antoniou, I., 2003, “Wind Tunnel Measurements on two Risø-B1 Airfoils,” Proc. 2003 European Wind Energy Conference & Exhibition, Madrid, Spain, June 16–19 (available only in CD-ROM).
10.
Johansen, J., Sørensen, N. N., and Hansen, M. O. L., 2001, “CFD Vortex Generator Model,” in Proceedings of the 2001 European Wind Energy Conference and Exhibition, Copenhagen, Denmark, July 2–7, edited by P. Helm and A. Zervos, WIP-Renewable Energies, Munich and ETA, Florence, pp. 418–421.
11.
Ferziger, J. H., and Peric´, M., 1996, Computational Methods for Fluid Mechanics, Springer–Verlag, Berlin.
12.
Patankar
,
S. V.
, and
Spalding
,
D. B.
,
1972
, “
A Calculation Procedure for Heat, Mass, and Momentum Transfer in Three-Dimensional Parabolic Flows
,”
Int. J. Heat Mass Transfer
,
15
, pp.
1787
–
1806
.
13.
Menter, F. R., 1993, “Zonal Two-Equation Turbulence Models for Aerodynamic Flows,” AIAA Paper No. 93–2906.
14.
Lugt, H. J., 1983, Vortex Flow in Nature and Technology, John Wiley & Sons, New York.
15.
Katz, J., and Plotkin, A., 1991, Low-Speed Aerodynamics: From Wing Theory to Panel Methods, McGraw–Hill, New York, pp. 25–51.
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