A Comparative CFD Study of Side-view Mirror and Side-view Camera Usages on a City Bus

Abstract

In this study, the effects of classical side mirrors and side-view cameras on the aerodynamic drag coefficient of a city bus model were investigated with Computational Fluid Dynamics (CFD). The surface profile of 1/5 scale bus was modeled with CATIA v5 program. Aerodynamic analyzes were per-formed with ANSYS Fluent® v18. Reynolds Average Navier-Stokes (RANS)-based Reynolds Stress Model (RSM) was used as the turbulence model. The ground effect was taken into consideration in all analyzes. The solution do-main for 5% blockage ratio was created. Inflation layers are used on the ve-hicle surface regarding velocity changes due to viscous effects. The mesh number independence of analyzes was examined for the bus model without side mirrors and provided for 1.3 M mesh element. The Reynolds number in-dependence of the analysis was investigated by using the optimum number of mesh. Free flow velocity of 90 m/s and above were found to be adequate for Reynolds number independence. The drag coefficient was calculated for the bus with side mirrors by using optimum mesh and wind speed as well. The drag coefficients for the bus with side mirrors and side view cameras were de-termined 0.53 and 0.521 respectively.

Keywords

• drag coefficient
• reynolds stress model
• aerodynamic drag of the bus