Numerical approach on drag reduction for automotive vehicles

Mateus Brizotti, Patrick Rambaud and Florian Visentin


VORTEX ANALYSIS without CONTROL SYSTEM
Table of Contents


        In this part, we did stationnary simulations without the blowing control system. To visualize the vortices, we  defined different planes at the rear of the car. The pressure streamlines are represented on these planes. Here are the results that we got.

  

                                    

On the right picture, we can clearly see where the vortices are localized at the rear window of the car. We notice that the vortices grow bigger progressively and that the centers of the vortices get closer and closer towards the center of the car. From these datas, we determined the Ψ and θ angles which defines the location of the central axis which passes through the center of each vortex.






Picture of the centers of vortexes for 3d simulation (Velocity Inlet: 40m/s & 50m/s)



Drag Force:






These results confirm that the drag evolution evolves with the square velocity inlet "V". "A" represents the total car area, "Fx" the total drag force due to the pressure drag and the shear drag and "Cx" the drag coefficient of the car.