Microscopic pumping of viscous liquids with single cavitation bubbles

Reese, Hendrik; Schädel, Robin; Reuter, Fabian; Ohl, Claus‐Dieter

doi:10.1017/jfm.2022.480

Cited by 19 publications

(6 citation statements)

References 30 publications

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“…Peter et al simulated laserinduced microjets, neglecting viscosity and phase transition, and obtained the result that the microjet velocity was consistent with experimental results [10]. Reese et al simulated the dynamics of cavitation bubbles, neglecting the effects of phase change as in our study [35]. To close the system, a stiffened gas equation of state (SG EoS) was adopted.…”

Section: Multiphase Flow Simulationsupporting

confidence: 70%

Design Exploration of Initial Bubbles for Higher-Speed Laser-Induced Microjets

2023

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Laser-induced microjets are advantageous for yielding high-speed and convergent microjets shape. However, owing to the need for high-power laser devices, reducing the required laser power is a prerequisite for convenience in practical use. This study aimed to optimize initial multiple bubbles design and find the dominant parameters for efficient microjet generation. For this purpose, the bubble design was optimized using an evolutionary algorithm-the covariance matrix adaptation evolutionary strategy. In addition, the dataset of solutions obtained through the optimization process was analyzed via principal component analysis (PCA). The optimization and analysis revealed that a higher microjet velocity could be obtained when a single bubble was generated near the tube wall, and an optimal total bubble volume was observed corresponding to this optimization. In addition, this approximate optimal solution we obtained was confirmed to reduce 88% of total initial energy compared to that of the typical solution. The result shows possibility to improve the efficiency of microjet generation and reducing the laser power.

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Section: Multiphase Flow Simulationsupporting

confidence: 70%

Design Exploration of Initial Bubbles for Higher-Speed Laser-Induced Microjets

2023

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“…2020), perforated plates (Gonzalez-Avila, Song & Ohl 2015; Reese et al. 2022) or spheres (Zhang et al. 2018; Li et al.…”

Section: Introductionmentioning

confidence: 99%

“…The jet dynamics is frequently characterised by a stand-off parameter (Lindau & Lauterborn 2003;Supponen et al 2016;Lauterborn et al 2018) computed as the ratio of the distance between the bubble nucleation position and the boundary (d) and the maximum radius attained by the bubble after its creation (R max ). If the cavity collapse occurs next to boundaries other than a plane, for instance, irregular or curved surfaces (Tomita et al 2002;Blake, Leppinen & Wang 2015;Wu et al 2018a;Li et al 2019b;Aganin, Kosolapova & Malakhov 2022) like pillars (Kadivar et al 2021;Koch et al 2021b), fibres (Mur et al 2023), corners (Mahmud, Smith & Walmsley 2020;Zhang et al 2020), crevices (Andrews, Fernández Rivas & Peters 2020;Trummler et al 2020), perforated plates (Gonzalez-Avila, Song & Ohl 2015; Reese et al 2022) or spheres (Zhang et al 2018;Li et al 2019a;Zevnik & Dular 2020;Ren et al 2022), the anisotropy does not have one predominant direction and, thus, the use of a single stand-off parameter (e.g. d/R max ) is no longer sufficient to fully characterise the system.…”

Section: Introductionmentioning

confidence: 99%

Bubble nucleation and jetting inside a millimetric droplet

et al. 2023

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In this work we present experiments and simulations on the nucleation and successive dynamics of laser-induced bubbles inside liquid droplets in free-fall motion, i.e. a case where the bubbles are subjected to the influence of a free boundary in all directions. Within this spherical millimetric droplet, we have investigated the nucleation of secondary bubbles induced by the rarefaction wave that is produced when the shock wave emitted by the laser-induced plasma reflects at the drop surface. Interestingly, three-dimensional clusters of cavitation bubbles are observed. Their shape is compared with the negative pressure distribution computed with a computational fluid dynamics model and allows us to estimate a cavitation threshold value. In particular, we observed that the focusing of the waves in the vicinity of the free surface can give rise to explosive cavitation events that end up in fast liquid ejections. High-speed recordings of the drop/bubble dynamics are complemented by the velocity and pressure fields simulated for the same initial conditions. The effect of the proximity of a curved free surface on the jetting dynamics of the bubbles was qualitatively assessed by classifying the cavitation events using a non-dimensional stand-off parameter ${\Upsilon\hskip -1,05em -\,}$ that depends on the drop size, the bubble maximum radius and the relative position of the bubble inside the drop. Additionally, we studied the role of the drop's curvature by implementing a structural similarity algorithm to compare cases with bubbles produced near a flat surface to the bubbles inside the drop. Interestingly, this quantitative comparison method indicated the existence of equivalent stand-off distances at which bubbles influenced by different boundaries behave in a very similar way. The oscillation of the laser-induced bubbles promotes the onset of Rayleigh–Taylor and Rayleigh–Plateau instabilities, observed on the drop's surface. This phenomenon was studied by varying the ratio of the maximum radii of the bubble and the drop. The specific mechanisms leading to the destabilisation of the droplet surface were identified.

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“…The ambient pressure p ∞ = 101 325 Pa is applied at the exit of the gap. See Zeng et al (2018Zeng et al ( , 2020; Reese et al (2022) for further details on the numerical implementation.…”

Section: Experiments and Simulationmentioning

confidence: 99%

Jetting enhancement from wall-proximal cavitation bubbles by a distant wall

Zeng,

Zhang,

Tan

et al. 2024

J. Fluid Mech.

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An additional distant wall is known to highly alter the jetting scenarios of wall-proximal bubbles. Here, we combine high-speed photography and axisymmetric volume of fluid (VoF) simulations to quantitatively describe its role in enhancing the micro-jet dynamics within the directed jet regime (Zeng et al., J. Fluid Mech., vol. 896, 2020, A28). Upon a favourable agreement on the bubble and micro-jet dynamics, both experimental and simulation results indicate that the micro-jet velocity increases dramatically as $\eta$ decreases, where $\eta =H/R_{max}$ is the distance between two walls $H$ normalized by the maximum bubble radius $R_{max}$ . The mechanism is related to the collapsing flow, which is constrained by the distant wall into a reverse stagnation-point flow that builds up pressure near the bubble's top surface and accelerates it into micro-jets. We further derive an equation expressing the micro-jet velocity $U_{jet}=87.94\gamma ^{0.5}(1+(1/3)(\eta -\lambda ^{1.2})^{-2})$ , where ${\gamma =d/R_{max}}$ is the stand-off distance to the proximal wall with $d$ the distance between the initial bubble centre and the wall, $\lambda =R_{y,m}/R_{max}$ with $R_{y,m}$ the distance between the top surface and the proximal wall at the bubble's maximum expansion. Viscosity has a minimal impact on the jet velocity for small $\gamma$ , where the pressure buildup is predominantly influenced by geometry.

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Microscopic pumping of viscous liquids with single cavitation bubbles

Cited by 19 publications

References 30 publications

Design Exploration of Initial Bubbles for Higher-Speed Laser-Induced Microjets

Design Exploration of Initial Bubbles for Higher-Speed Laser-Induced Microjets

Bubble nucleation and jetting inside a millimetric droplet

Jetting enhancement from wall-proximal cavitation bubbles by a distant wall

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