Computational Simulation of Tractor-Trailer Gap Flow with Drag-Reducing Aerodynamic Devices 2005-01-3625

Computational simulations of the Modified Ground Transportation System¹ (M-GTS), a 1/14^th-scale simplified tractor-trailer geometry, are performed at both laboratory and full-scale Reynolds numbers using the NASA overset grid code OVERFLOW². Steady Reynolds' Averaged Navier-Stokes (RANS) simulations are conducted to deepen the understanding of tractor-trailer gap flow structure, and to ascertain the time-averaged efficacy of tractor cab extenders and trailer-face splitter plates in reducing aerodynamic drag in typical crosswinds. Results of lab-scale simulations compare favorably to body force and particle image velocimetry (PIV) data obtained from University of Southern California (USC) experiments for two tractor-trailer gap lengths. Full-scale simulations highlight model geometry limitations and allude to the use of splitter plates in place of, or in conjunction with, tractor cab extenders.