抄録
This paper analyzes experimentally the influence of the geometrical configuration on the aerodynamic drag using a bluff body such as a notchback vehicle. The effective parameters which reduce the aerodynamic drag were clarified by parametric study of the geometrical configuration. These effective parameters were defined as the apparent angle. For the notchback, it is found that the critical geometries which increase the aerodynamic drag, such as the critical geometry for the box type, exist when using these apparent angles. On the other hand, it is also found that the wake of these bluff bodies consists of the arch vortex and the trailing vortices, by means of flow visualization and velocity vector distributions. As a result, based on understanding of the wake structure, it is clarified that the aerodynamic drag increases at a certain rear apparent angle which is caused by the arch vortex. The apparent angle is proposed for the effective configuration parameter.
