Aero-acoustics study of coupled cavities in close proximity along a rectangular flow duct at low Mach number

Abstract

Abstract In present study, a series of flow induced noise experiments were investigated by a coupled cavity with low Mach number flow. A new signal processing method was derived to analyze the turbulence sound field and its propagation inside the coupled cavity region. In order to investigate the sound field in the presence of flow throughout the coupled cavity regions, a transfer function technique for transducer signals was developed. Experimental result and analysis show that the significant sound attenuation effect is caused by the pressure fluctuation that gives rise to canceling waves along the main duct section. In the presence of the acoustic excitation and the duct flow, the Rossiter type of feedback is the dominant mechanism responsible for the sound amplification effect. This type of feedback mechanism also results in relatively tonal sound generations at various frequencies within the working bandwidth of the coupled cavities.