A mesh refinement study was conducted and it was determined, given the computational
power available, that the optimal mesh for the study of the body and under-tray consisted of
approximately 1.5 million cells. The surface of the model was given an inflated mesh
consisting of five layers of inflation with an expansion rate of 1.2 between each layer. The
remainder of the mesh was generated using tetrahedral cells with a minimum edge length of
1.4mm and a maximum of 106mm. The software solved the Reynolds Averaged Navier
Stokes (RANS) equations, using the Shear-Stress-Transport (SST) turbulence model.
As an example of a typical result obtained, the effect of directing the exhaust gases into the
rear diffuser tunnels under the car on the lift coefficient for a number of exhaust gas
temperatures was investigated, and the results are shown in Fig. (1) for a vehicle speed of 15
m/s. It is clearly evident that the downforce is increased as the mass flow rate and gas
temperature increase