Two computational methods, one based on the solution of the vorticity transport equa-
tion, and a second based on the solution of the Reynolds-Averaged Navier-Stokes equa-
tions, have been used to simulate the aerodynamic performance of a horizontal axis wind
turbine. Comparisons have been made against data obtained during Phase VI of the
NREL Unsteady Aerodynamics Experimental and against existing numerical data for a
range of wind conditions. The Reynolds-Averaged Navier-Stokes method demonstrates
the potential to predict accurately the flow around the blades and the distribution of aero-
dynamic loads developed on them. The Vorticity Transport Model possesses a consid-
erable advantage in those situtations where the accurate, but computationally efficient,
modelling of the structure of the wake and the associated induced velocity is critical,
but where the prediction of blade loads can be achieved with sufficient accuracy using
a lifting-line model augmented by incorporating a semi-empirical stall delay model. The
largest benefits can be extracted when the two methods are used to complement each
other in order to understand better the physical mechanisms governing the aerodynamic
performance of wind turbines