Cavitation microstreaming patterns in single and multiple bubble systems

By Paul Tho, Richard Manasseh, Andrew Ooi. Journal of Fluid Mechanics, 2007

235 citations recorded by the source corpus.

Cavitation microstreaming is a well-known phenomenon; however, few flow visualizations or measurements of the velocity fields have been conducted. In this paper micro-PIV (particle image velocimetry) measurements and streak photography were used to study the flow field around a single and two oscillating bubbles resting on a solid boundary. The mode of oscillation of the bubble was also measured in terms of the variation in the radius of the bubble and the movement of the bubble's centroid so that the streaming flow field could be accurately related to the bubble's oscillatory motion. The mode of oscillation was found to vary primarily with the applied acoustic frequency. Several modes of oscillation were investigated, including translating modes where the bubble's centroid moves along either a single axis, an elliptical orbit or a circular orbit. The flow field resulting from these oscillation modes contains closed streamlines representing vortical regions in the vicinity of the bubble. The translating modes were observed to occur in sequential order with the acoustic excitation frequency, changing from a translation along a single axis, to an elliptical orbit and finally to a circular orbit, or vice versa. Following this sequence, there is a corresponding transformation of the streaming pattern from a symmetrical flow structure containing four vortices to a circular vortex centred on the bubble. Despite some inconsistencies, there is general agreement between these streaming patterns and those found in existing theoretical models. Volume and shape mode oscillations of single bubbles as well as several different cases of multiple bubbles simultaneously oscillating with the same frequency and phase were also investigated and show a rich variety of streaming patterns.

Subfields: Biomedical Engineering, Materials Chemistry, Mechanics of Materials

View Paper: https://www.semanticscholar.org/paper/788d54baac01340c6bbb335b5cc9ba7c71b4f598

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In Biomedical Engineering

Citations in the corpus

Applications of Acoustics and Cavitation to Noninvasive Therapy and Drug Delivery (2008, background): “…is dictated by the compressibility of the gas phase and associated physical effects include sound scattering, cavitation microstreaming (Elder 1959; Tho et al 2007), subharmonic noise generation (Eller & Flynn 1968; Eller 1974; Leighton & Phelps 1997; Longuet-Higgins 1990; Prosperetti 1975),…”
Applications of power ultrasound in food processing. (2014, unknown): “Figure reproduced with permission from Tho et al. (2007).”
A fast microfluidic mixer based on acoustically driven sidewall-trapped microbubbles (2009, background): “This oscillation generated pressure and velocity fluctuations in the surrounding liquid, resulting in a phenomenon known as microstreaming (Tho et al. 2007).”
The Physical and Chemical Effects of Ultrasound (2011, background): “Fig. 1.3 Cavitation microstreaming patterns around a 272 μm radius bubble excited at acoustic frequencies 9 and 11 kHz (reproduced from Tho et al. (2007) with permission)”