Abstract
The effect of rear-spoiler attached at rear end of commercial bus on the aerodynamic characteristics was numerically investigated. Numerical simulations have been carried out for three-dimensional turbulent flows around a bluff-based body and actual bus body. RNG k-Ã turbulence model with the MARS scheme was used for the evaluating the aerodynamic forces. The Reynolds number based on the free stream velocity and projected frontal area of model was 1.75 ~10 6 . The results showed that details of the three-dimensional wake flow in the immediate rear of bus body and the effect of rear-spoiler on the wake structure. A maximum of 14% reduction in drag coefficient was achieved for a model with a rear-spoiler.