3D steady RANS simulations on the DriVear car model: The impact of the computational grid parameters

Automotive designers and engineers are constantly working on the optimization of aerodynamic performance of vehicles to reduce fuel consumption and gas/particulate emissions. In recent decades, among several car models, the DrivAer model has become one of the most adopted car bodies for generic studies. Although wind-tunnel (WT) testing and Computational Fluid Dynamics (CFD) are systematically used to investigate the aerodynamic performance of cars, it is still unclear to what extent CFD results might be affected by computational parameters as the grid. This paper investigates the impact of the surface grid resolution (SgR), total prism layer height (yT), and first layer height (y1), on the aerodynamic performance of the scaled (1:4) DrivAer model, using the 3D steady Reynolds-averaged Navier-Stokes (RANS) approach. The RANS results, validated with the WT data, showed that especially yT and y1 can be crucial for an accurate prediction of drag (CD) and lift (CL) force coefficients on the DrivAer model.