Transient Simulation Research on Automobile Aerodynamic Lift Based on LBM Method
In order to improve the limitation of steady-state automobile aerodynamic lift characteristics in finite volume method, the Lattice Boltzmann Method (LBM) was conducted on transient simulation of automobile aerodynamic lift. This proposed method utilized adaptive wake refinement feature to obtain a series of regular fluid particles for macroscopic fluid and combined large eddy simulation (LES) with wale-viscosity model to study the transient characteristics of automobile aerodynamic lift. In this numerical investigation, using the international standard automobile MIRA model, the temporal and spatial characteristics of rear velocity field and vorticity field were analyzed, whose results had agreement with the wind tunnel test data. It was showed that the elaborate information of flow field around the car-body and the aerodynamic lift could be more accurately described. A pair of asymmetric non-periodical and inward twisting rear vortexes in the car rear flow field was found, while it squeezed and dragged each other in different eddy scales. This result also indicated the aerodynamic lift to oscillate in a certain amplitude scope, markedly different from the simulated result of steady state automobile aerodynamic lift, which is more close to real driving conditions.