Experimental Investigation of Aerodynamics of a Car Model

In this study, the time-average velocity in the near wake of a two-dimensional Notch-Back car model located in the wake of a trailer has been investigated. Experiments were carried out in an open circuit low-speed wind tunnel made by FaraSanjeshSaba Ltd, in Iran. Results show that at close spacing, time-average velocity profile behind the car has a maximum peak due to the interaction of the jet fluid with the wake of the car, such that with increased vehicle spacing, the jet fluid effect creating the maximum velocity peak gradually fades. In addition, along with increasing vehicle spacing, the velocity in the wake of the car starts to growquickly. To measure the drag coefficient it was preferred to use the wake-survey method combined with the equation recently derived by Van Dam. The dimensionless distance between vehicles derived is based on the length of the front vehicle ranging from 0.1 to 3. It was observed that the car drag coefficient experiences a rising trend at the beginning and then descendingalong dimensionless distance of 0.1 to 1.3, compared to the individual case. In farther distances it will be less pronounced than the individual case.