François Delassaux

External aerodynamics o Correlation CFD/experiments on full scale DrivAer model in collaboration with Ford Germany o Improvement of GEKO turbulence model performances using loop optimization on the model coefficients Internal aerodynamics o Project Manager to develop a numerical procedure for new airvent design with Coanda effects o Loop optimization development on 35 parameters on a global computation (CAD, grid, turbulence modelling, numerical setup, etc.) o Compliance on global cost, quality, delay, support for co-workers and reporting to other teams connected to the project Thermal cooling o Development of loop optimization to create the most efficient cooling plate shape for maximizing batteries cooling

• Support to collaborators on CFD tools and numerical methods

• Writing of internal note for technical subjects Software: AVL FIRE, Fluent, ANSA, ModeFrontier, Python

Unsteady computational study of external aerodynamics flow in automotive industry using hybrid RANS/LES method The main goal of this PhD is to develop an unsteady numerical method to study the external aerodynamic flow around real vehicles. The first part of the study focuses on the flow around simplified geometries, such as 25° Ahmed bodies (with sharp and rounded edges on the back of the body), in order to determine the optimal turbulence model, mesh setup and numerical parameters. Computational Fluid Dynamics (CFD) results are compared to experimental data reported in literature conducted in the La Ferté Vidame wind tunnel. Based on this study, Shear-Stress Transport Delayed Detached Eddy Simulation (SST DDES) demonstrates superiority over Reynolds Averaged Navier-Stokes (RANS), Scale Adaptive Simulation (SAS) and Stress Blended Eddy Simulation (SBES) turbulence models, regarding both drag and lift coefficients predictions, and flow topology. Secondly, the numerical procedure is adapted for a real vehicle, the Peugeot 308 SW estate car. A substantial experimental campaign was carried out in the Groupement d'Intérêt Economique Souffleries Aéroacoustiques Automobiles (GIE S2A) wind tunnel to provide data against which the numerical results are compared. Given the geometric complexity of a real vehicle, the car is simplified for this study as follows: the front air inlets are closed, the underbody is smoothed with additional panels and the wheels are replaced by fairings. DDES computations show encouraging results. A significant improvement of the flow topology is obtained with DDES compared to RANS models. However, the prediction of the lift coefficient remains a major difficulty with these hybrid methods. SOFTWARES: ANSA, Fluent Meshing, Fluent, ENSIGHT, Tepclot, Matlab

GOALS:

- Implementation of k-ε and k-ω PANS turbulence models (Partially-Averaged Navier-Stokes) in ANSYS Fluent software using UDF ASSIGNMENTS:

- bibliographical studies

- coding the UDF

- validation on simplified test cases: flow study around a surface-mounted single cube on the ground and cylinder with triangular section type SOFTWARE:

- ANSYS Fluent, UDF (C++), Ensight (post-processing)