Application of SNGR Method to Compute Aero-Vibro-Acoustics of Heavy-Duty Rear-View Mirrors

Flow-induced noise inside cab interior (also termed aerodynamics-induced interior noise) is nowadays perceived as a key factor when assessing the quality of heavy-duty vehicles. In order to satisfy the turnaround time required for current product development, a simplified hybrid numerical approach has been adopted. It couples the SNGR (Stochastic Noise Generation and Radiation) method with a finite element method. The SNGR approach uses RANS (Reynolds Averaged Navier Stokes) for fast CFD (Computational Fluid Dynamics) computations, and is based on a stochastic model to synthesize turbulent velocity fluctuations. These fluctuations are then used to reconstruct aeroacoustic sources based on lighthill's equation. Several rear-view mirror configurations have been chosen to validate this numerical approach. The results are in good agreement with the experiments performed on track. The numerical approach is finally demonstrated as a fast method that can be applied to assess and rank early designs in a short time for the purpose of reducing aerodynamics-induced interior noise.