Numerical simulations and experimental validation on passive acoustic emissions during bubble formation. (15th January 2018)

• Record Type: Journal Article
• Authors: Liu, Jingting; Wang, Wu; Chu, Ning; Wu, Dazhuan; Xu, Weiwei
• Is Part Of: Applied acoustics. Volume 130(2018)
• Page Start: 34
• Page End: 42
• Publication Date: 2018-01-15
• Subjects: Large eddy simulation -- Acoustic analogy -- Passive acoustic emissions -- Signal processing; Acoustical engineering -- Periodicals; Periodicals; 620.2
• DOI: 10.1016/j.apacoust.2017.09.005
• Languages: English
• ISSNs: 0003-682X

Abstract

Highlights: Numerical prediction of passive acoustic emission during submerged bubble detachment has been performed. Bubble formation processes are recorded by hydrophone and high speed camera. Spectrum and spectrogram of passive acoustic signals are illustrated. Simultaneous analysis of bubble shape and passive acoustic signal are showed. Abstract: In this paper, the volume of fluid (VOF) model in conjunction with continuum surface force (CSF) model is applied to numerically investigate the single bubble formation process in the bubble columns. Meanwhile, the hybrid method (large-eddy simulation (LES) and acoustic analogy method) is used for bubble acoustic prediction. Experimental results provide a reliable validation of the numerical results. Adaptive filtering technique and time–frequency analyses are adapted for the numerical acoustic data at the gas velocity of 0.1 m/s. The spectrum and spectrogram approaches indicate that the numerical acoustic data covers two principal frequency components, in which, one is the bubble generation rate and the other is the natural frequency of volumetric bubble oscillation. By combining the studies of flow field and acoustic signals, volumetric bubble oscillation is found to be excited by an axial water jet up into the bubble, immediately following the bubble detachment. The results of this study lead to the proposition that numerical simulation method could be applied to well understanding of the physics behind the passive acoustic emission.