Comparison of upwind and downwind operation of the NREL Phase VI Experiment

The predominant wind turbine architecture currently is horizontal-axis, three-bladed, upwind rotors (rotor upwind of tower). Several large downwind research turbines were constructed in the past and a few small downwind models were commercially available in the 1980\u27s. Downwind turbines have the potential for lower average loads and thus lower mass/cost; however, problems such as fatigue and noise arise from the rotor interacting with the tower wake. Recent advances in offshore wind energy, including turbines on floating platforms, has renewed interest in large downwind designs that can be placed far from shore