The unpredictable nature of bubble evolution

Jack, Lawless,; Keeler, Jack S.; Gaillard, Antoine; Hazel, Andrew L.; Juel, Anne

doi:10.1038/s41598-022-23231-8

Cited by 3 publications

(1 citation statement)

References 36 publications

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“…The nonspherical oscillations affect bubble stability, and eventually leading the bubble to collapse. [23][24][25][26] Therefore, bubble behaviors might be disturbed by neighboring bubbles. Figure 3 shows bubble behaviors observed by the long focal length microlens with a recording rate of 4.5×10 5 fps at a resolution of 256 × 128 pixels (each pixel of the images is about 1 µm), and the observation region was about 256 µm×128 µm.…”

Section: Coalescence and Fragmentationmentioning

confidence: 99%

Behaviors of cavitation bubbles driven by high-intensity ultrasound

Huang 黄,

Li 李,

Feng 冯

et al. 2024

Chinese Phys. B

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Bubble behaviors are modulated by the primary and secondary acoustic fields in a multi-bubble system. To explore the translational motion of bubbles in cavitation liquids containing high-concentration cavitation nuclei, evolutions of bubbles were recorded by a high-speed camera, and translational trajectories of several representative bubbles were traced. It is found that translational movements of bubbles are always accompanied by the fragmentation and coalescence of bubbles, and for bubbles smaller than 10μm, the possibility of bubble coalescence is enhanced when the spacing of bubbles is less than 30μm. Measured signals and their spectra show the presence of strong negative pressure, broadband noise, and various harmonics, which imply that multiple interactions of bubbles appear in the region of high-intensity cavitation. Due to the strong coupling effect, the interaction between bubbles is random. A simplified triple-bubble model was developed to explore the interaction patterns of bubbles affected by the surrounding bubbles. Patterns of bubble interaction, such as attraction, repulsion, stable spacing, and rebound of bubbles, can be predicted by the theoretical analysis, which is in good agreement with experimental observations. Mass exchange between the liquid and bubbles as well as absorption in the cavitation nuclei also plays an important role in multi-bubble cavitation, which may account for the weakening of the radial oscillations of bubbles.

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Section: Coalescence and Fragmentationmentioning

confidence: 99%

Behaviors of cavitation bubbles driven by high-intensity ultrasound

Huang 黄,

Li 李,

Feng 冯

et al. 2024

Chinese Phys. B

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Periodic dynamics in viscous fingering

Lawless,

Hazel,

Juel

2024

Proc. R. Soc. A.

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The displacement of a viscous liquid by air inside a Hele-Shaw channel is an archetype for nonlinear pattern-forming systems. Typically, bubbles or fingers of air propagate steadily at low values of the capillary number Ca = μ U * / σ , where μ is the viscosity of the liquid, U * is the speed of the bubble or finger and σ is the surface tension at the air–liquid interface. However, as the capillary number increases, the advancing interface can exhibit disordered pattern-forming dynamics. We demonstrate experimentally that a sustained, remote perturbation of the bubble tip can drive time-periodic dynamics. We exploit the propensity of a group of bubbles to propagate in steady spatial arrangements inside a Hele-Shaw channel with a centralized depth-reduction to apply a sustained pressure perturbation ahead of the bubble as it propagates. The oscillation cycle is initiated by the splitting of the bubble tip, via the Saffman–Taylor instability, which is promoted by the local flow-field conditions. The restoral of the bubble tip follows naturally because the system is driven by a fixed flow rate and the perturbed bubble is attracted to the weakly unstable, steadily propagating state that is set by the ratio of imposed viscous and capillary forces. The splitting and restoral mechanisms do not rely on the specific perturbation used in this study, suggesting a generic mechanism for periodic dynamics of propagating curved fronts subject to steady flow-field perturbations.

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Stable bubble formations in a depth-perturbed Hele-Shaw channel

Lawless,

Keeler,

Hazel

et al. 2024

Phys. Rev. Fluids

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The propagation of polydisperse bubbles inside a rectangular Hele-Shaw channel by the constant volumetric flux flow of an ambient viscous liquid is generally unsteady; pairs of neighboring bubbles will either separate or coalesce because their propagation speeds increase monotonically with their sizes. Thus, any group of bubbles will eventually rearrange itself in order of decreasing size, individual bubbles will separate, and, crucially, there are no stable multiple-bubble states. Remarkably, the introduction of a small axially uniform elevation to the channel's lower boundary (on the order of a percent of the channel's depth) leads to the creation of stable multiple-bubble states and, thus, disrupts the usual reordering by bubble sizes. The constituent bubbles of such states lie in alternation on opposite sides of the elevation. The elevation provides a mechanism for the trailing bubbles to reduce their propagation speeds when approaching their preceding nearest neighbors. The stable multiple-bubble states are always led by the smallest bubble while the trailing bubbles can be arranged in any order and, thus, their number grows factorially as the number of bubbles increases. Published by the American Physical Society 2024

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The unpredictable nature of bubble evolution

Cited by 3 publications

References 36 publications

Behaviors of cavitation bubbles driven by high-intensity ultrasound

Behaviors of cavitation bubbles driven by high-intensity ultrasound

Periodic dynamics in viscous fingering

Stable bubble formations in a depth-perturbed Hele-Shaw channel

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