Comparison of Turbulent Models and Discretization Schemes Based on OpenFOAM for the Numerical Simulation of the Flow Around an Automotive Standard Model

Abstract:

The flow around the 35° Ahmed model is numerically explored by using three different turbulence models （the realizable k-ε （RKE）， the Spalart-Allmaras （SA）， and the shear stress transport k-ω （SST）） and four different velocity convection schemes （the linear upwind （LU）， the linear upwindV （LUV）， the localblend， and the total variation diminishing （TVD）） based on OpenFOAM. Then， two other software platforms （FLUENT and STARCCM+） are also used as references. It shows that the numerical results of RKE and SST are more reasonable than those of SA. The stable LUDSV and localblend convective scheme both partly weaken the wake oscillation caused by numerical instability， but only the TVD scheme entirely suppresses this oscillation behavior. The drag coefficients predicted by the three software platforms are all in good agreement with those of the experiment， and the error of OpenFOAM using TVD is the smallest， only 0.7%. In addition， OpenFOAM and STARCCM+ can obtain a more reasonable and similar three-dimensional wake flow structure， while FLUENT overestimates the strength of the streamwise C-pillar vortex.

Key words:vehicle aerodynamics;OpenFOAM;turbulence model;convection scheme;steady simulation