Large eddy simulation of flow around a bluff body of vehicle shape

The turbulent flow with wake, reattachment and recirculation is a very impo rtant problem that is related to vehicle dynamics and aerodynamics. The Sma gorinsky Model (SM), the Dynamics Subgrid Scale Model (DSM), and the Lagran gian Dynamic Subgrid Scale Model (LDSM) are used to predict the three-dimen sional flow field around a bluff body model. The Reynolds number used is 45 ,000 based on the bulk velocity and the height of the bluff body. The fully developed turbulent flow, which is generated by the driver part, is used f or the inlet boundary condition. The convective boundary condition is impos ed on the outlet boundary condition, and the Spalding wall function is used for the wall boundary condition. We compare the results of each model with the results of the PIV measurement. First of all, the LES predicts flow be havior better than the k-epsilon turbulence model. When we compare various LES models, the DSM and the LDSM agree with the PIV experimental data bette r than the SM in the complex flow, with the separation and the reattachment at the upper front part of the bluff body. But in the rear part of the blu ff body, the SM agrees with the PIV experimental results better than them. In this case, the SM predicts overall flow behavior better than the DSM and the LDSM.