Simulation techniques for the aerodynamic study of automotive components

When it comes to vehicle aerodynamics, wheels have always a primary importance due to their high drag contribution, expecially if they cannot be shrouded. For a vehichle such as a F1 car, wheel total drag contribution reaches high percentage, such as 30-40%. This study has the purpose to investigate the aerodynamic behaviour of a non-deformable rotating flat sided wheel without hubs. The testcase is supposed to have dimensions of a 2018 F1 front tyre. A Computational Fluid Dynamics (CFD) approach, by using Open-FOAM (OF), is used to catch the main flow features, vortex structures and forces involved. A lot of time is spent to get a good mesh around the wheel with OF internal mesher due to the ground presence. Widely used Spalart-Allmaras, κ-ω SST, Realizable κ-ε codes are implemented first. Then the analysis is concentrated to κ-ω SST LM and several built-in DES models: κ-ω SST DES, Spalart-Allmaras DES, Spalart-Allmaras DDES. In the transtional model the goal is to look for laminar-turbulent boundary layer transition. In the DES/DDES approaches it is desiderable to see more detailed flow fields and a reduction of turbulent viscosity in regions where the mesh is fine enough to perform a local LES. As a consequence, comparisons between models output data and catching capabilities are made. Furthermore, the feasibility of using a DES approach with respect to RANS in automotive problems is analyzed in the case mesh grids don’t allow a fine wall resolution. Experimental data matching the testcase considered don’t exist but literature, however, provides a good agreement with the results for similar researches.