Optimal subharmonic emission of stable bubble oscillations in a tube

Fan, Yuzhe; Li, Haisen; Fuster, Daniel

doi:10.1103/physreve.102.013105

Cited by 7 publications

(3 citation statements)

References 39 publications

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“…We integrate (2.1)–(2.3) and (2.5) (satisfying (2.4) and (2.6)) on the finite volume grids using the numerical method discussed by Fuster & Popinet (2018) also used by Fan, Li & Fuster (2020), Saini (2022), Saini et al. (2022, 2024) and extended to include thermal effects by Saade, Lohse & Fuster (2023).…”

Section: Problem Set-upmentioning

confidence: 99%

Direct numerical simulations of microlayer formation during heterogeneous bubble nucleation

Saini,

Chen,

Zaleski

et al. 2024

J. Fluid Mech.

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In this article, we present direct numerical simulation results for the expansion of spherical cap bubbles attached to a rigid wall due to a sudden drop in the ambient pressure. The critical pressure drop beyond which the bubble growth becomes unstable is found to match well with the predictions from classical theory of heterogeneous nucleation imposing a quasi-static bubble evolution. When the pressure drop is significantly higher than the critical value, a liquid microlayer appears between the bubble and the wall. In this regime, the interface outside the microlayer grows at an asymptotic velocity that can be predicted from the Rayleigh–Plesset equation, while the contact line evolves with another asymptotic velocity that scales with a visco-capillary velocity that obeys the Cox–Voinov law. In general, three distinctive regions can be distinguished: the region very close to the contact line where dynamics is governed by visco-capillary effects, an intermediate region controlled by inertio-viscous effects away from the contact line yet inside the viscous boundary layer, and the region outside the boundary layer dominated by inertial effects. The microlayer forms in a regime where the capillary effects are confined in a region much smaller than the viscous boundary layer thickness. In this regime, the global capillary number takes values much larger then the critical capillary number for bubble nucleation, and the microlayer height is controlled by viscous effects and not surface tension.

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Section: Problem Set-upmentioning

confidence: 99%

Direct numerical simulations of microlayer formation during heterogeneous bubble nucleation

Saini,

Chen,

Zaleski

et al. 2024

J. Fluid Mech.

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“…The equations are solved using the All-Mach implementation (Popinet 2015;Fuster & Popinet 2018), where the one-fluid approach is used to solve the modelling equations. This solver has been used successfully already to investigate some aspects of the interaction of an oscillating bubble and a rigid tube by Fan, Li & Fuster (2020), and interactions of collapsing bubbles with a free surface by Saade et al (2021). The set-up for numerical simulations is shown in figure 4(a), where a spherical-cap-shaped bubble is initialised in a square domain of size 100 times the initial radius of curvature of this bubble.…”

Section: Viscous Correctionmentioning

confidence: 99%

On the dynamics of a collapsing bubble in contact with a rigid wall

et al. 2022

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This work reveals that the dynamic response of a spherical cap bubble in contact with a rigid wall depends on the effective contact angle at the instant prior to collapse. This parameter allows us to discriminate between two regimes in which the mechanisms of interaction between the collapsing bubble and its surrounding medium differ significantly: when the contact angle is smaller than $90^{\circ }$ , a classical jet directed towards the wall is observed, whereas if the initial contact angle is larger than $90^{\circ }$ , an annular re-entrant jet parallel to the wall appears. We show that this change of behaviour can be explained using the impulse potential flow theory for small times, which shows the presence of a singularity on the initial acceleration of the contact line when the contact angle is larger than $90^{\circ }$ . Direct numerical simulations show that although viscosity regularises the solution at $t > 0$ , the solution remains singular at $t=0$ . In these circumstances, numerical and experimental results show that the collapse of flat bubbles can eventually lead to the formation of a vortex ring that unexpectedly induces long-range effects. The role of the bubble geometry at the instant of maximum expansion on the overall collapse process is shown to be well captured by the impulse potential flow theory, which can be generalised easily to other bubble shapes. These results may find direct application in the interpretation of geophysical flows as well as the control and design of biomedical, naval, manufacturing and sonochemistry applications.

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“…An important characteristic of subharmonics is their abrupt appearance when control parameters are varied. There is a threshold beyond which they are suddenly generated, as it has been studied for an uncoated bubble [8] , [9] , [10] , [11] , [12] and for a coated bubble [13] , [14] , [15] , [16] . All these works study the dynamics of a bubble excited by a linear continuous pressure source, but they do not consider the nonlinear retroaction of the bubble vibrations on the acoustic field.…”

Section: Introductionmentioning

confidence: 99%