Numerical approach on drag reduction for automotive vehicles

Mateus Brizotti, Patrick Rambaud and Florian Visentin

Table of Contents

        Alhough a full modelisation of the car geometry is necessary to analyse the real aerodynamics features of the car, a lot of work can be done using a simplified car geometry which is called Ahmed’s body. This geometry is modelised in scale 1/4th with Gambit software. A picture of such a geometry is represented in figure 1.


         The following dimensions are used in this project : L=1.044 m, H=0.288 m and w=0.389 m. This geometry represents the rear window with an inclination angle of 25°. The window length la is equal to 0.222 m.
       Below are two pictures of the 3D Mesh that we made with Gambit software and that we used to do the calculations with starccm+ software.

        This mesh contains 600 000 cells divided as follows :

* 450 000 cells in the volume where the vortices appears.

                                 * 150 000 cells in the outer part of the whole volume.