Investigation of cavity flow noise attenuation using acoustic liners in the locked-on state

The focus of this study is on utilizing acoustic liner technology to control the aerodynamic noise generated by cavities. The primary objective is to investigate the impact of these passive control measures on the coupled noise of low-speed cavity flows and shear layer turbulence. The design of the acoustic liner incorporates the characteristics of cavity-coupled noise, and experimental measurements are conducted to assess the configurations of the lining at different installation positions. The near-field and far-field noise were measured to evaluate the noise reduction performance of the liner, and the flow characteristics of the shear layer were measured to assess the effect of the acoustic liner on the cavity flow. It was found that the acoustic liner was effective in reducing cavity noise. Furthermore, the study reveals that the effectiveness of the acoustic liner is influenced by its different installation positions. In this study, the noise reduction mechanism of the acoustic liner was also investigated to effectively suppress the coupling of cavity self- sustained oscillations and acoustic resonance. Finally, the influence of acoustic liner on the flow characteristics in the shear layer of the cavity was explored. This study guides the application of acoustic liner in cavity noise control.