Technical Reports

Wind Tunnel Tests of Trailer and Container Models to Determine the Independent Influence of Height and Gap Spacings and Trailer Undercarriage Shielding on Aerodynamic Forces Occurring During Railroad Transport

  • 01
  • Mar
  • 1980
AUTHOR: Andrew G. Hammitt
OFFICE: RPD
REPORT NUMBER: FRA/ORD-80/51
SUBJECT: Facilities & Test Equipment
KEYWORDS: Intermodel, TOFC, COFC, Piggyback Aerodynamics, Train Resistance
ABSTRACT: A series of wind tunnel tests have been run on scale model trains of 40 ft. containers and trailers. The models were 1/43 scale. A train of five models was used with forces and moments measured on the center model. A variety of spaces were used between the models. The height of the container models was varied and the undercarriage of the trailers was protected with shields of different heights. These tests are the latest in a series designed to determine the aerodynamic forces on containers and trailers on flatcars. This series provides additional information on the effect of different container block height and gap spacings and the effect of spacing on the forces on trailers with different amounts of shielding up to large values of yaw angle. The tests showed that axial force initially increased with yaw angles up to 30 to 40° and then decreased. This decrease is caused by the axial component of the wind velocity decreasing with increasing yaw 'angle until it becomes zero at 90° yaw angle. The side forces increase with yaw angle reaching a maximum at about 60°. The moment data shows that the side force is applied about half way up the block at a point a little forward of the center. On the trailers, the point of application is still about half way between the top'of the trailer and the ground for all shieldings used and either ahead of or behind the centerline depending on the amount of shielding.

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