Investigation on the characteristics of flow-induced vibration and noise of acoustic window with embedded compound acoustic black holes

Abstract

In recent decades, acoustic black hole (ABH) structures have shown significant potential for suppressing structural vibrations and noise radiation. However, the ABH structure has not been applied to panel–cavity noise control under heavy fluid loading. In this study, a hybrid numerical approach was used to analyse the vibro-acoustic response suppression mechanism of a compound acoustic black hole (CABH) acoustic window under turbulent boundary layer (TBL) excitation. Both sides of the acoustic window interact with the water. The results show that the local vibration modes of the CABH lead to a strong interaction between the structure and damping material. The amplitude of the high-order modal wavenumber spectra of the CABH was small, which weakened the spatial coupling between the TBL pressure and the structure. The coupling strength between the CABH acoustic window and the internal sound field was reduced, causing noise suppression inside the cavity. To further examine the noise reduction performance of the CABH panel cavity system, a flow-induced experiment with a large-scale CABH acoustic window was carried out in a large cavitation channel, and the results showed significant hydrodynamic self-noise reduction.