The transient exterior flow field of a mini-van was computed by large eddy simulation(LES)

and then the noise characteristic was predicted using FW-H acoustic model based on Lighthil-Curle acoustic analogy theory.The local shape of the mirror was modified to reduce the aerodynamic noise.Finally a real vehicle road test was implemented

with the test velocities from 60 km/h to 120 km/h.The result shows that the vehicle noise has been noticeably reduced

or even down to 1.2 dB

by modifying the mirror shape.