As part of a DOE-sponsored study, the aerodynamic drag of l/87th-scale coal cars was measured in a wind tunnel. The goal of the experiment was to measure the difference in drag between full and empty cars so as to determine if drag mitigation efforts are warranted. In addition, several simple drag-reduction concepts were studied that were designed to minimize impact on the current coal-car geometry and operation. Covering the coal cars, although impractical, demonstrated that a 42% reduction in drag is possible with no crosswind. Two vertical dividers attached to the existing internal bracing yielded a 23% reduction in wind-averaged drag. The effects of internal bracing, triangular dividers, and crosswind were also investigated. Drag measurements were made for model yaw angles from zero to 10 deg and a wind-averaged drag coefficient was calculated for each configuration. The presence of internal bracing yielded a 5% reduction in the wind-average drag which suggests that simple geometry modifications can have significant effects. Two triangular dividers attached to the existing bracing yielded a 16% reduction relative to the empty-car configuration. Extending these dividers to the top of the car produced a 25% reduction in wind-averaged drag. Without crosswind, these two divider configurations yielded 15% and 17%, respectively. These results illustrate the potential reduction achievable with minimal modifications and cost.
Reducing the aerodynamic drag of empty coal cars
Reduzierung des aerodynamischen Widerstandes von leeren Kohlenwaggons
2005
5 Seiten, 10 Bilder, 3 Tabellen, 4 Quellen
Conference paper
English
Reducing the aerodynamic drag of empty coal cars
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