A method for the reduction of bus drag

A method for the reduction of bus drag Saving energy has become one of the main challenges of human beings today. Among energy consumers, transportation represents a significant part, especially ground transportation. Flow control is the best way to reduce the fuel consumption by reducing drag. In the present thesis, a method of reducing the drag of an approximately 1:25 scale bus models by the introduction of thin upstream-placed flat plate was investigated. The investigation was carried out in the Munzur University's closed circuit wind tunnel. The basic aerodynamic effects of a range of plate lengths (l), a range of gaps between plate and bus (g), and a range of Reynolds numbers (Re) were assessed for 0° yaw. A three-dimensional printer that utilizes the fused deposition modeling (FDM) technology was used to construct the bus models and plates. Details of the flow between the bus models and plates were obtained using the smoke-wire flow visualization. The tunnel was equipped with an external one-component force balance and this was used for direct measurement of drag. The main purpose of this thesis is to check the feasibility of using such external devices for reducing drag on the full scale buses. It was found that to reach a maximum reduction of the drag coefficients of the bus models, flat plate with a dimensionless plate length of l*=0.7 must be placed g*=0.1 upstream of the buses. For Model-1, this method produces a system drag that is 84.1% that of the Model-1 alone, at Re=200000. However, for Model-1, this method produces a system drag that is 98.9% that of the Model-2 alone, at Re=200000.