Numerical approach
on drag reduction for automotive vehicles

Mateus Brizotti, Patrick Rambaud and Florian Visentin

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.

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.