Aeroacoustic prediction and experimental validation of a cross-flow fan: Impact of interface configuration

Abstract

This study examines the effect of interface configuration on the aeroacoustic prediction of cross-flow fans using a combined experimental and numerical approach. Unsteady Reynolds Averaged Navier Stokes (URANS) simulations, coupled with the Ffowcs Williams-Hawkings (FW-H) acoustic analogy, were conducted to capture both aerodynamic behavior and noise emissions. Two interface strategies were evaluated: a single-interface and a dual-interface configuration. While steady-state simulations provided basic aerodynamic trends, they were not able to capture the unsteady flow structures that are important for noise prediction. The URANS approach allows resolution of these transient features. The results indicate that the single-interface configuration tends to better preserve coherent vortical structures and provides acoustic predictions that are more consistent with the measured tonal components, including the blade-passing frequency (BPF). In contrast, the dual-interface configuration shows improved aerodynamic performance prediction but reduced acoustic levels. This difference may be associated with the attenuation of unsteady flow structures, which could be influenced by numerical dissipation effects related to the interface treatment. However, this interpretation remains qualitative and has not been quantitatively verified in the present study. The results highlight the trade-off between aerodynamic accuracy and acoustic resolution, emphasizing the importance of interface treatment in fan noise modeling.