Assessment of a Discontinuous Galerkin Method for the Simulation of the Turbulent Flow around the DrivAer Car Model

Abstract

The turbulent flow over the DrivAer fastback model is here investigated with an order-adaptive discontinuous Galerkin (DG) method. The growing need of high-fidelity flow simulations for the accurate determination of problems, e.g., vehicle aerodynamics, promoted research on models and methods to improve the computational efficiency and to bring the practice of Scale Resolving Simulations (SRS), like the large-eddy simulation (LES), to an industrial level. An appealing choice for SRS is the Implicit LES (ILES) via a high-order DG method, where the favourable numerical dissipation of the space discretization scheme plays directly the role of a subgrid-scale model. Implicit time integration and the p-adaptive algorithm reduce the computational cost allowing a high-fidelity description of the physical phenomenon with very coarse mesh and moderate number of degrees of freedom. Two different models have been considered: (i) a simplified DrivAer fastback model, without the rear-view mirrors and the wheels, and a smooth underbody; (ii) the DrivAer fastback model, without rear-view mirrors and a smooth underbody. The predicted results have been compared with experimental data and CFD reference results, showing a good agreement.

Large Eddy Simulations for the Ahmed Car at 25° Slant Angle at Different Reynolds Numbers

“…However, some recent workshops results and publications seem to indicate that a further increase in accuracy can be obtained by moving to Large Eddy-Simulation (LES) mostly in combination with wall-functions (WFLES) (e.g. [4], [5], [6]). While successful applications of WFLES have been demonstrated in other areas, like the simulation of high-lift full aircraft configurations [7] (at least for wind-tunnel scale), the reliability of using such methods in industrial automotive simulations still needs to be established.…”