Abstract: In this paper, with two Shanghai GM vehicles as study object, the multi-reference frame (MRF) scheme of moving reference frame (MRF) method is applied to the simulation of wheel rotation, both CFD simulation and wind tunnel test are conducted on the aerodynamic characteristics of vehicle under both conditions of the standstill and rotation of wheel, and by comparing the results of simulation and wind tunnel test, the correctness of MRF method in simulating aerodynamic effects of wheel rotation is verified. Based on the analysis on the flow-field simulation results, the generation mechanism of aerodynamic resistance of rotating wheel and the effects of wheel rotation on wake structure and rear-end pressure are analyzed, and the flow-field action mechanism of the change in C_d caused by wheel rotation is explored. According to the features of flow-field distribution, optimization schemes for reducing wheel resistance are proposed and the results of simulation show that the optimal scheme can significantly reduce C_d. The study provides the flow-field simulation scheme with CFD for simulating the aerodynamic effects of wheel rotation and analyzes the mutual action mechanism of complex flow-field related to wheel rotation, providing helpful reference for the aerodynamic optimization development of wheels and rear-end.

Key words: automotive aerodynamics, moving reference frame method, wheel rotation effects, numerical simulation, wind tunnel test