Analysis of Sound Sources for a Generic Car Mirror

Abstract

The study seeks to scrutinise the predictive prospects of scale-resolving Detached-Eddy Simulations (DES) in comparison to unsteady RANS (URANS) for the prognosis of aero-acoustics dipole sources. This engineering realm has recently gained importance for the transportation industry due to the enhanced aeroacoustic noise contributions associated with higher travelling speeds and the increasing legal restrictions for noise emission. As noise-reduction techniques have improved significantly in the area of vibro-acoustics, flow-induced noise is shifted into the focus of vehicle and aircraft manufacturers by means of the development of reliable source-prediction methods. In the present effort, attention is confined to the flow over generic car mirror mounted on a flat-plate. Results are reported for time-averaged and transient pressure signals in comparison with experimental data provided by DaimlerChrysler Research and Technology (Höld et al. 1999; Siegert et al. 1999). Employing the same computational environment, the total sound pressure level predictions obtained from DES outperform URANS by approximately 20dB.