Abstract: In order to find an efficient and high accuracy simulation method for the aerodynamic noise in vehicle HVAC ducts, three commonly-used methods, i.e. acoustic analogy, direct simulation and co-simulation analysis methods are compared and the effects of sound source surface on the accuracy of acoustic analogy method are emphatically analyzed, based on the standard HVAC duct model co-issued by German vehicle manufacturers Audi, BMW, Daimler, Porsche and Volkswagen. Firstly, RNG turbulence model and SST k-ω DES model are adopted to solve the steady state and transient flow field respectively. Then, the acoustic analogy, direct simulation and co-simulation methods are used to calculate far field radiation noise respectively. The results of simulation and test show that the time-averaged characteristics of flow-field in HVAC duct obtained with RNG turbulence model are overall agree with PIV measurement data and the fluctuated pressure spectra on duct wall surfaces simulated by SST k-ω DES model are basically consistent with test results. Among commonly-used simulation methods, the acoustic analogy method with the penetrable surface surrounding the jet turbulence at duct outlet as sound source surface has the highest accuracy

Key words: vehicle HVAC ducts, aerodynamic noise, turbulence, accuracy