Analysis of Turbulence Models Applied to CFD Drag Simulations of a Small Hatchback Vehicle 2016-36-0201

Thanks to advances in Computational Fluid Dynamics - CFD codes, i.e. algorithms and turbulence models, complex CFD vehicles simulations are increasing not only in academia, but also in the industry itself. The aim of the simulations is to verify the aerodynamic behavior of a car at early stages of the project, when no prototype is available, and to reduce the total aerodynamic development time of a new vehicle.

The turbulence model considered in the CFD simulation should be able to capture the main flow effects around the vehicle. Most importantly, the predicted total drag value of the vehicle has to be comparable to the values obtained in wind tunnel tests. The main focus of the presented work is a comparison of wind tunnel and CFD results of the same small production hatchback vehicle. Different turbulence models are considered in the simulation ranging from steady state approaches, k-epsilon and k-omega SST, to transient models, DDES and the newly developed Stress-Blended Eddy Simulation - SBES. Flow profiles of the different turbulence models are shown in order to analyze flow effects around the vehicle. The presented results show a good agreement between test and simulation.