Multiple Spark-Generated Bubble Interactions

Abstract

The complex interactions of two and three spark-generated bubbles are studied using high speed photography. The corresponding simulations are performed using a 3D Boundary Element Method (BEM) code. The bubbles generated are between 3 to 5 mm in radius, and they are either in-phase or out-of-phase with one another. The possible interaction phenomena between two identically sized bubbles are summarized. Depending on their relative distances and phase differences, they can coalesce, jet towards or away from one another, split into smaller bubbles, or 'catapult' away from one another. The 'catapult' effect can be utilized to generated high speed jet in the absence of a solid boundary or shockwave. Also three bubble interactions are highlighted. Complicated phenomena such as bubble forming an elliptical shape and bubble splitting are observed. The BEM simulations provide insight into the physics of the phenomena by providing details such as detailed bubble shape changes (experimental observations are limited by the temporal and spatial resolution), and jet velocity. It is noted that the well-tested BEM code [1,2] utilized here is computationally very efficient as compared to other full-domain methods since only the bubble surface is meshed.

Pulsating Tandem Microbubble for Localized and Directional Single-Cell Membrane Poration

“…1d). Similar bubble dynamics have been observed in an unconstrained fluid medium using spark-generated vapor bubbles of millimeter size [15]. …”

Experimental study on interaction and coalescence of synchronized multiple bubbles

“…Experimental efforts have been made to study bubble interactions, using methods such as optical breakdown (laser) [43][44][45][46][47] , electric discharge [48][49][50] , small charge explosion 51 , and pressure impulse 52 . Bubble interaction has also been studied with numerical methods such as the boundary integral method coupled with fast multiple expansions [53][54][55][56] .…”

“…There are few studies in the literature for interaction of three bubbles. Khoo et al 48 and Fong et al 49 carried out a few cases for three bubbles, where the bubble behavior was complicated, due to a number of factors such as bubble phases, sizes and positions. The current experiment is capable of generating three evenly distributed synchronized bubbles of the same size.…”

Liquid jet formation through the interactions of a laser-induced bubble and a gas bubble

“…27 Studies of the motion of two cavitation bubbles generated directly beneath a free surface have shown that competition of the effects from the free surface and the bubbles' mutual interactions can result in a wide range of bubble behavior, including the jet formation. 28 Investigations of the interactions between a pair of bubbles have shown that the speed and direction of the liquid jet could be controlled by adjusting three dimensionless governing parameters of the bubble pair, [29][30][31][32][33] including the relative temporal difference of their initiation, τ, the relative size of the bubbles, ρ, and the relative initiation distance, γ. τ is defined as ∆t/T exp1 , where ∆t is the temporal difference of the bubble pair's initiation, and T exp1 is the expansion time of the first bubble, called bubble 1, from its initiation to its maximum volume. ρ is defined as R max2 /R max1 , where R max1 is the maximum radius of bubble 1, and R max2 is the maximum radius of the second bubble, called bubble 2. γ is defined as d/(R max1 +R max2 ), where d is the initial distance in between the bubble pair when they are just generated.…”