Noise emitted from a generic side-view mirror with different aspect ratios and inclinations

Noise radiated from flow past different configurations of Half-Round Mirror (HRM) mounted on a plate has been investigated using computational aeroacoustics (CAA). The Stress-Blended Eddy Simulation (SBES), together with the Ffowcs Williams-Hawkings (FW-H) acoustic analogy, was employed to predict near field flow and far-field noise, respectively. The numerical methodology was verified and validated for the standard HRM by comparing against several previously published numerical and experimental data sets. Further, the (i) choice of different type of grids for CAA and (ii) applicability of methods such as Kirchhoff integrals and FW-H evaluated using near field inputs computed from SBES are assessed. The predictions from the SBES–FW-H methodology show good agreement with both the previously published experimental and numerical results for the standard HRM case. As a next step, the effect of induced noise from the HRM for a different a) aspect ratios (AR) ranging from 1 to 2.5 and b) inclination of the mirror towards the plate (θ) ranging from 0° to 32° were investigated. For all the investigated cases, the distribution of the radiated noise exhibits a dipole-like structure closer to the plate and a monopole-like structure away from the plate. By inclining the mirror closer to the mounting plate reduced the emitted noise both in the vertical and lateral directions of the wake, whereas an increase in the AR of the mirror increases the induced noise considerably. The findings from the current study can provide a deeper understanding for effectively mitigating the induced aerodynamic noise from side-view mirrors.