Some techniques for reducing the tower shadow of the DOE/NASA Mod-0 wind turbine tower
Detailed wind speed profile measurements were made in the wake of 1/25 scale models of the tower and in the wake of certain full-scale components to determine the magnitude of the speed reduction (tower shadow). Test results are presented for the following shadow abatement techniques: removal of diagonals, replacement of diagonals with simulated tension rods, replacement of diagonals and horizontals with round cross-section members, installation of elliptical shapes on horizontal members, installation of airfoils on vertical members, application of surface roughness to vertical members. All techniques offered some reduction in tower shadow at all wind directions. Small diameter tension rods employed as wind tower diagonals resulted in the greatest increase in tower wake velocity, up to approximately 90% of the free stream value. The tower shadow abatement gained from the installation of tension rods, ellipses, weather-vaning airfoils, and/or surface roughness must be further evaluated on a case-by-case basis for their structural characteristics and cost-effectiveness.
- Research Organization:
- National Aeronautics and Space Administration, Cleveland, OH (USA). Lewis Research Center
- DOE Contract Number:
- EX-76-A-29-1004
- OSTI ID:
- 5923091
- Report Number(s):
- DOE/NASA/20370-79/17; NASA-TM-79202
- Country of Publication:
- United States
- Language:
- English
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