Citation

Park CS, Jeon SW, Lee KJ, Kim JS, Oh JG, Park JC, Lee HS, Choi YS. J. Forensic Sci. 2012; 57(4): 1108-1113.

Affiliation

Central District Office of National Institute of Scientific Investigation, Daejeon 305-348, Korea. Division of Mechanical Engineering, Korea University, Seoul 136-701, Korea. Division of Document and Image Analysis, National Institute of Scientific Investigation, Seoul 158-707, Korea. Division of Traffic Engineering, National Institute of Scientific Investigation, Seoul 158-707, Korea.

Copyright

(Copyright © 2012, American Society for Testing and Materials, Publisher John Wiley and Sons)

DOI

10.1111/j.1556-4029.2012.02082.x

PMID

22372464

Abstract

  This case report describes a noncontact traffic accident involving a motor scooter and a tractor-trailer with a focus on the wind-drag effect. We used load cells to measure the drag force acting on a substantially similar motor scooter when a substantially similar tractor-trailer passes by it, taking into consideration various speeds of the tractor-trailer and distances between the two vehicles. A three-dimensional steady-state flow analysis was also performed by using the CFX program for computational fluid dynamics to examine the streamlines and the pressure distribution around the tractor-trailer at various speeds. From the experiment, for a separation distance of 1.0 m (3.28 ft) and a speed of 90 km/h (55.9 mph), the maximum resultant drag force is 124.5 N (28 lb); this constitutes a degree of force that could abruptly disrupt the stability in maneuvering by an operator who is unaware of the approaching tractor-trailer. In addition, a single equation that relates the tractor-trailer speed to the drag force that acts on the motor scooter was derived on the basis of the Reynolds number (Re) and the wind-drag coefficient (C(d) ): C(d)  = 1.298 × 10(-7) Re.

Language: en