ELSEVIER Journal of Wind Engineering and Industrial Aerodynamics 69-71 (1997) 413-422 JOURNAL OF windengineering Mean wind and turbulence characteristics due to induction effects near wind turbine rotors David E. Neff, Robert N. Meroney* Fluid Mechanics and Wind Engineering Program, Civil Engineering Department, Colorado State University, Fort Collins, CO 80523, USA Abstract The objective of this study was to place a model wind turbine into a wind tunnel and measure the wind characteristics in the vicinity of the spinning rotor for a variety of flow conditions. A 0.53 meter diameter model wind turbine was placed in the Meteorological Wind Tunnel facility at Colorado State University. Four different approach flow conditions were studied. These were two different mean wind speeds (6 and 7.6 m/s) and two different turbulence conditions (0.1% and 1.5% intensity). For each of these test conditions the three-dimensional wind field was measured between 3 rotor diameters upwind to ½rotor diameter downwind. The rotor power coefficient versus tip speed ratio was also obtained. 1. Introduction Aerodynamicists currently use wind field and turbulence information to calculate the character of dynamic loading that large wind-generator rotors received [14]. Unfortunately, these turbulence scales and intensities may be distorted by the pressure of the rotor flow field before they actually interact with the rotor blades. Indeed, wind- generator induction effects and streamline divergence caused by the hub and tower may significantly distort free wind field values. In recent years, a limited number of model and field scale measurement studies have examined near- and far-field turbine rotor wakes [5-7]. These wake studies were made to evaluate the influence of upwind turbines on downwind installations; little information appears in the literature con- cerning possible induction effects. It is the purpose of this paper to provide experi- mental model data on the wind field surrounding a single wind turbine rotor disk. These data should provide an improved physical insight into the induction effects of the air flow as it approaches the wind turbine. This insight should in turn improve an analytical model's predictive capabilities. * Corresponding author. 0167-6105/97/$17.00 © 1997 Elsevier Science B.V. All rights reserved. PII S01 67-6 1 05 (97)00 173-6