Drag Coefficient Determination Of A Bus Model Using Reynolds Number Independence

Abstract

Full-scale wind tunnel tests require too much time and cost to determine drag coefficients of vehicles. In this study, drag coefficient of a blunt bus model was tried to be determined using Reynolds number independence. A low speed wind tunnel having a free flow velocity is 28 m/s and has a rectangular cross section of 292 mm high and 292 mm wide, was used in experiments. The flow around the bus model was simulated with ANSYS CFX at wind tunnel conditions. As a result, aerodynamic drag coefficient of the bus model was determined as 0,66 and 0,65 according to results of CFX and experiment respectively after Reynolds number 57000. It is determined that the drag coefficient of the blunt vehicles can be determined by using low speed wind tunnel and Reynolds number independence.