Dynamics of the passive pulsation of a surface-attached air bubble subjected to a nearby oscillating spark-generated bubble

Abstract

The dynamics of a spark-generated bubble (a discharge short circuit) generated in proximity to a stationary air bubble attached to a plate is experimentally investigated by high-speed photography. Numerous interesting and complex interactions occur during the two bubble coupling pulsation owing to the deformation properties or “free surface” characteristics supplied to the plate by the attached air bubble. Complex bubble jetting behaviors, such as bubble splitting, jets away from the plate, variable directional jets, and multidirectional jets are observed. Passive pulsation of the air bubble is observed in response to the spark bubble. Moreover, five types of bubble behaviors are summarized: bubble coalescence, the air bubble skirt phenomenon, the “mountain”-shaped bubble, and the “cup cover”-shaped air bubble with or without splitting. To develop a better understanding of the coupling interactions between the two bubbles during their oscillations, four types of bubble volume–time curves are summarized using the image outline identification code established to obtain information regarding the bubble shape. The complex phenomena during the two-bubble interactions, such as the bubble jetting direction, air bubble shapes, and volume–time curves, are summarized as graphs and are highly dependent on the bubble size ratio, dimensionless cavitation bubble oscillation time, and initial displacement parameter.

Dynamics of a buoyant pulsating bubble near two crossed walls

“…The jet direction is calculated to be 26 according to Eq. ( 11), which is consistent with the result based on the measurement of the bubble profile in the experimental image (25 ). Note that we define the jet direction by the Kelvin impulse, characterizing the movement trend of bubbles.…”

“…One of the most important and interesting features of bubble dynamics near a rigid wall is the creation of high-speed liquid jets. 1,[23][24][25][26][27][28][29][30][31] These jets point toward the wall in the case of small-scale bubbles and interact with the flow field close to the wall. In the late stage of bubble collapse, they may even hit the wall.…”

Manipulation of bubble collapse patterns near the wall of an adherent gas layer

“…In recent years, researchers have found that near the water–air free interface or bubbles, cavitation bubbles can generate jets away from the interface or bubbles [14] , [32] , [33] , [34] , [35] , [36] , [37] , [38] , [39] , [40] , [41] , [42] . Gonzalez et al [32] fabricated mushroom-shaped microcavities on SiO2/Si substrates, which can effectively capture air underwater.…”