Aerodynamic noise prediction of passenger vehicle with hybrid detached eddy simulation/acoustic perturbation equation method

Aerodynamic noise significantly affects the ride comfort of vehicle. A hybrid method combining detached eddy simulation and acoustic perturbation equations was used together with wind tunnel experiment to perform the aerodynamic noise investigation of a passenger vehicle. A good agreement of exterior overall sound pressure level and turbulent pressure spectra was found between the experiment and simulation with 260 million cells. Both turbulent and acoustic pressures were used as power input in statistical energy analysis, and the predicted interior noise is consistent with the experiment. The turbulent and acoustic pressures show a closely related spatial distribution, while the distribution patterns are different due to the distinction in their ways of propagation. The turbulent pressure travels downstream together with flow, while the acoustic pressure radiates homogeneously. Through statistical energy analysis, the major aerodynamic noise sources are identified as underbody for frequencies under 200 Hz and windows above 200 Hz, respectively. Finally, the studies of mesh resolution show that the finer mesh with 260 million cells can provide better results, while the coarser mesh with 90 million cells performs relatively poorly.