Observation and analysis of interactive phenomena between microbubbles and underwater shock wave

Abstract

This paper reports the observation and analysis of the microbubble motion induced by an underwater shock wave. In the analysis, Herring's bubble motion equation was numerically solved using an experimental shock wave pressure profile. The pressure attenuation of the rebound shock wave of a microbubble was also estimated by numerical simulation. The motion behaviors of the microbubbles during their interaction with an electric discharge shock wave, such as their rebound, shock wave generation, and microjet formation, were observed by magnified visualization. To improve the observation accuracy, spatial positioning control of the microbubbles was employed. The experimentally determined time variation of the diameter of the microbubbles when they collapsed spherically was in agreement with the results of the numerical analyses, and the latter also revealed a very high pressure of the rebound shock wave. There were, however, discrepancies between the experimental and analytical results for non-spherical collapse. It is thought that spherical collapse produces stronger rebound shock waves and that the probability of such collapse increases with decreasing diameter of the bubble. In addition, it was demonstrated that single and multiple microbubbles moved vigorously after interaction with a shock wave and the latter coalesced into a single bubble within several hundred microseconds.

Scaling laws for bubble collapse driven by an impulsive shock wave

“…These experiments included a variety of underwater shock wave generation methods, such as lithotripters (Philipp et al 1993), lasers (Wolfrum et al 2003) and underwater explosions (Kodama & Takayama 1998). They have confirmed, for instance, that the radial bubble dynamics are well predicted by numerically solving the Keller-Miksis equation (Keller & Miksis 1980;Philipp et al 1993;Wolfrum et al 2003;Abe et al 2015). The formation of a thin liquid jet in the direction of shock propagation has been imaged and its average velocity found to be in the range 20-200 ms −1 (Philipp et al 1993;Ohl & Ikink 2003).…”

“…The uncertainty on the scaled pressure waveform at the bubble location can be further quantified using spherical cavitation bubble theory as a second method. Indeed, previous studies have demonstrated the Keller-Miksis (Keller & Miksis 1980) equation to describe well experimentally visualised shock-driven radial bubble dynamics even upon strong bubble deformation (Philipp et al 1993;Wolfrum et al 2003;Abe et al 2015), especially when the shock wave's pressure is measured at the bubble location with a fibre-optic hydrophone. Here, the simpler Rayleigh (Rayleigh 1917) and Rayleigh-Plesset (Plesset 1949) equations are also briefly shown and their limitations commented.…”

“…A fundamental understanding of the physics behind shock-bubble interactions at the single bubble level can help to control and optimise them in applications leveraging bubble-jets on demand. A number of past studies have managed to visualise shock-bubble interactions at the millimetric (Haas & Sturtevant 1987;Layes, Jourdan & Houas 2009) and even micrometric (Philipp et al 1993;Kodama & Takayama 1998;Ohl & Ikink 2003;Wolfrum et al 2003;Abe et al 2015) scale despite the experimental challenges imposed by their small spatial and temporal scales. These experiments included a variety of underwater shock wave generation methods, such as lithotripters (Philipp et al 1993), lasers (Wolfrum et al 2003) and underwater explosions (Kodama & Takayama 1998).…”

“…2003; Abe et al. 2015) scale despite the experimental challenges imposed by their small spatial and temporal scales. These experiments included a variety of underwater shock wave generation methods, such as lithotripters (Philipp et al.…”

Experimental verification of shock sterilization for marine Vibrio sp. using microbubbles interacting with underwater shock waves

“…The mean diameter of the bubbles from type-A and type-B generators was about 90 m and 50 m, respectively. Abe et al have analyzed the rebound pressures of the collapsing microbubbles by solving Herring bubble motion equations with the experimental pressure profile of the incident shock wave [13]. It is apparent that the rebound shock pressure of a 50 m diam.…”