Numerical investigation of the influence of tire deformation on different vehicle configurations

Wheels and wheel houses contribute up to 25% of the total aerodynamic drag of passenger cars. Both rim and tire geometries induce complex flow separation mechanisms in a highly unsteady regime. To have a clearer understanding of the flow around wheels and inside the wheel house, a detailed high-fidelity CFD setup with rotating wheels is essential. Tire deformation is modelled with an analytical approach, validated against FEA results. Realistic tire geometries are investigated with OpenFOAM with the purpose of assessing how deformation affects the aerodynamic performance of the wheels and the total drag of the car. To do so, different car heights and different tire deformation levels are investigated separately and then combined to assess the effect that each of them entails. The evaluations are done on the basis of the drag coefficient of the vehicle.