Co-simulation approach for computational aero-acoustic modeling: Investigating wind-induced noise within two-way radio microphone ports cavity

Abstract

Wind-induced noise (aeroacoustic) can cause problem with any outdoor microphone applications, notably impacting the performance of telecommunication mobile. One prominent source in two way radios is the microphone port cavity. In this article, the noise characteristics behaviour is studied at scale-up of microphone port cavity through computational aero-accoustics (CAA) numerical simulation and experimental test. This research aims to investigate the wind-induced noise (aeroacoustic) generated inside the microphone port cavity at various wind orientation angles (wind direction) and distance radii, r. A direct-hybrid co-simulation CAA method, utilizing the LES-WALE (Wall-Adapting Local Eddy-viscosity) and Ffowcs William-Hawking (FW-H) models, is employed to obtain the near-field noise source and far-field noise patterns inside a microphone port cavity. The simulations are conducted using the scFLOW2Actran software. Richardson extrapolation and Grid Convergence Index (GCI) are applied to evaluate the accuracy of the grid independency in numerical simulations.The findings reveal that the leading edge, centre and trailing edge are the primary noise sources and generations inside a microphone port. The study indicates that the noise level in the microphone port cavity is characterized by low frequency noise.The results indicates that at an observation of angles of 0° and distance radii of 0.2 m, the wind noise level is higher compared to other orientation angle and distance radii. This can be attributed to the proximity to the noise source  at this location. The directivity pattern of noise propagation exhibits a typical dipole pattern observed at observation angles of 0° to 45°. Numerical results align well with the experimental results from the wind tunnel test, demonstrating the feasibility of the proposed approach for flow-acoustic coupling application. This research holds significant value for engineers as it provides a comprehensive understanding of the physical phenomena involved in microphone port design.