Abstract
Aerodynamic drug reduction by installing wake control aero-devices at the rear end corners is tried for commercial vehicles like buses and tucks having perpendicular rear end surface. In deed drug reduction of ~18% is confirmed with the authorsÂ’ wind tunnel test using a bus model. The present CFD calculation is made to understand the detailed mechanism of such a significant drug reduction and to design further effective aero-devices. The flow characteristics around the bus model without wake control aero-devices is simulated as a first step in this paper. Attention is paid to reproduce the experimental result of pressure distribution on the rear end base. As a result, separation promoter of a small flat plate is found to be effective to reproduce the experimental profile.