The Investigation of Flow Characteristic Around A Bus Model by CFD Method and Improvement of Drag Force by Passive Flow Control Method

In this study, aerodynamic drag coefficient of 1/64 scaled bus model was determined by the computational fluid dynamics (cfd) method. flow analyzes were performed at 15 m/s, 20 m/s, 25 m/s ve 30 m/s in x direction, between the range of 173000-346000 reynolds numbers. flow analysis was made in fluent® program. the aerodynamic drag coefficient (cd) of the bus model was determined as 0.657 on average, the distribution of total drag was determined as pressure friction based. after the flow visualization, the areas are detected where forms aerodynamic drag on the model bus. a triangular section flow control element has been developed to improve the flow structure and decrease the pressure based drag. the flow control element is an equilateral triangle with a diameter of 15 mm and positioned on the front bumper of the model bus. the aerodynamic drag coefficient of model 1 bus was determined as 0.623. with this passive flow control method, the aerodynamic drag coefficient improved by %5.27. the effect of this improvement on fuel consumption is about 3 % at the high vehicle speed. the effect of this aerodynamic improvement on the annual fuel consumption of a bus has been evaluated.