Experimental and numerical investigation on bubble dynamics near a free surface and a circular opening of plate

The dynamics of a buoyant pulsating bubble near two crossed perpendicular rigid boundaries (a horizontal and a vertical wall) are studied using the boundary element method combined with the method of mirror images. The Kelvin impulse and the elastic mesh velocity method are used to calculate the direction and volume of the liquid jet generated during bubble collapse. The numerical results show good agreement with experiments. An increase in buoyancy causes a local high-pressure zone at the root of the jet to move toward the bottom of the bubble, causing the jet to rotate upward toward the vertical wall. At a certain position, with the change in buoyancy, the dimensionless bubble volume at the instant of jet impact reaches a minimum when the jet direction is horizontal, with a peak in the dimensionless jet velocity occurring. A comprehensive parametric study of jet characteristics, including jet direction, velocity, and relative volume (the volume ratio of the jet to the bubble at the instant of jet impact), is carried out in terms of buoyancy and the standoff distances to the two walls. The Blake criterion can be used to judge whether a bubble jet is pointing obliquely upward or downward, provided that it deviates significantly from the horizontal direction. Depending on the buoyancy, the jet characteristics at different standoff distances are found to exhibit three distinct patterns of behavior. Finally, we discuss the changes in the jet velocity and relative volume as the buoyancy is varied.

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“…Because the physical process is unsteady, the bubble surface velocity potential needs to be updated 40,57,58 using the Bernoulli equation…”

Section: Numerical Model a Physical Model And Numerical Methodsmentioning

confidence: 99%

Dynamics of a buoyant pulsating bubble near two crossed walls

Liu

Wang

et al. 2021

Physics of Fluids

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“…Method. Actually, the process of underwater explosion near structures is a complicated fluid-structure interaction (FSI) problem [22,23]. Two sorts of methods are usually used to solve this problem, namely, the Lagrangian method and Eulerian method [11,24].…”

Section: Coupled Eulerian and Lagrangianmentioning

confidence: 99%

Study on the Pressure Characteristics of Shock Wave Propagating across Multilayer Structures during Underwater Explosion

Meng

Cao

Ming

et al. 2019

Shock and Vibration

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e propagation of the shock wave across multilayer structures during underwater explosion is a very complex physical phenomenon, involving violent fluid-structure interaction (FSI) problems. In this paper, the coupled Eulerian-Lagrangian (CEL) method in AUTODYN is used to simulate the process of shock wave propagation and solve FSI problems. Firstly, the governing equation and the treatment of fluid and structure interface of the CEL method are briefly reviewed. Afterwards, two underwater explosion numerical models are established, and the results are compared with the empirical formula and experimental data, respectively, to verify the reliability of numerical solutions. e results obtained by this method show good agreements with those of the empirical formula and experiment. Furthermore, the model of the multilayer structures composed of two hemispherical shells and the fluid filled between the shells subjected to underwater explosion is established, and the pressure characteristics of the shock wave propagating across the multilayer structures are analyzed regarding the wave reflection and transmission. Finally, the effects of the shell thickness and the filled fluid type among the multilayer structures on the wave reflection and transmission are studied.

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“…Liu et al. (2017) investigated a bubble collapsing between a free surface and a submerged rigid boundary with a through-hole. Bubbles collapsing close to a fully submerged rigid boundary with a single through-hole have also been investigated, both experimentally (Lew, Klaseboer & Khoo 2007; Karri et al.…”

Section: Introductionmentioning

confidence: 99%

Bubble collapse near porous plates

2023

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The collapse of a gas or vapour bubble near a non-porous boundary is directed at the boundary due to the asymmetry induced by the nearby boundary. High surface pressure and shear stress from this collapse can damage, or clean, the surface. A porous boundary, such as a filter, would act similarly to a non-porous boundary but with reduced asymmetry and thus reduced effect. Prior research has measured the cleaning effect of bubbles on filters using ultrasonic cleaning, but it is not known how the bubble dynamics are fundamentally affected by the porosity of the surface. We address this question experimentally by investigating how the standoff distance, porosity, pore size and pore shape affect two collapse properties: bubble displacement and bubble rebound size. We show that these properties depend primarily on the standoff distance and porosity of the boundary and extend a previously developed numerical model that approximates this behaviour. Using the numerical model in combination with experimental data, we show that bubble displacement and bubble rebound size each collapse onto respective single curves.

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Experimental and numerical investigation on bubble dynamics near a free surface and a circular opening of plate

Cited by 62 publications

References 40 publications

Dynamics of a buoyant pulsating bubble near two crossed walls

Dynamics of a buoyant pulsating bubble near two crossed walls

Study on the Pressure Characteristics of Shock Wave Propagating across Multilayer Structures during Underwater Explosion

Bubble collapse near porous plates

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