Numerical study of effects of stand-off distance and gravity on large scale bubbles near a breach

He, Ming; Wang, Shiping; Ren, Shiquan; Zhang, Shuai

doi:10.1016/j.apor.2021.102946

Cited by 12 publications

(4 citation statements)

References 51 publications

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“…The simplest example of a porous material is a flat plate with a pattern of through-holes. Some research has investigated the problem of a plate with a through-hole bounding a free surface in relation to breaches of maritime hulls (Cui et al 2021(Cui et al , 2022He et al 2021). Similarly, Sun et al (2022b) investigated bubble collapse near a rigid surface with a gas-entrapping hole.…”

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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Section: Introductionmentioning

confidence: 99%

Bubble collapse near porous plates

2023

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“…The local damage effects of jet loads and bubble pulsation loads on ships cannot be ignored. Based on the previous studies, investigations on the dynamic behaviors of the underwater explosion bubble jet with different boundaries such as free surface [13][14][15], rigid boundary [16][17][18], elastic boundary [19][20], elastic-plastic boundary [21], and boundary with cracks [22,23] were conducted. However, there is little attention being paid to studying the underwater explosion between a structure on the water and a deformable seabed.…”

Section: Introductionmentioning

confidence: 99%

Numerical Simulation Research on Characteristics of Underwater Explosive Bubble Jet in Offshore Water

Chen

Qin²,

Meng³

et al. 2023

J. Phys.: Conf. Ser.

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Underwater explosions have always been a hot topic in the field of ship protection. When explosives explode in offshore waters, the influence of seabed and structural boundaries on shock wave propagation and bubble pulsation will become more complicated. In this paper, a numerical simulation study of the underwater explosion between a deformable seabed and a rigid boundary is carried out. Firstly, the ABAQUS software was used to establish a numerical model by using the CEL method. The seabed was regarded as a heavier fluid, and the density ratio of the seabed and water was used to describe the characteristics of the seabed. The validity of the model was verified by comparison with experiments. Then, a series of numerical simulations were carried out by adjust the position of the explosive, the thickness of water medium layer, and the density of the seabed. The results show that: when the position of the explosive is close to the seabed and the rigid boundary, the bubble pulsation period is longer. The water jet and the pulsating pressure of the bubbles have a strong impact on the structure when the explosive is located near to 1 times the theoretical maximum radius of the bubble. As the depth of the water decreases, it can be observed that the bubbles transform from “ellipsoid” to “nipple-like”, and finally tear into upper and lower halves. When the thickness of water medium layer is 1 times the theoretical maximum radius of the bubble, the incident pressure waveforms of the bubble pulsation and the water jet near the structure are chaotic, which is caused by the “tear” phenomenon of the bubble. As the density of the seabed increases, the depth of the intrusion of the bubbles into the seabed becomes smaller and the shape of the bubbles becomes flatter. The research results of this paper can provide reference for the protection design of ships.

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“…Meanwhile, a few scholars have expanded the research fields to study the features of the bubble near a discontinuous boundary. He et al [29] numerically investigated the effect of the stand-off distance on the bubble near a breach. The results revealed that the stand-off distances defined the inrush patterns, including inrush with a bursting bubble, inrush with a gourd-shaped bubble, and inrush with a floating bubble.…”

Section: Introductionmentioning

confidence: 99%