Investigation of Bubble Collapse and Water Jet Induced by Underwater Explosion in a Rectangular Tube

2012 ◽  
pp. 27-32 ◽  
Author(s):  
T. Koita ◽  
Y. Zhu ◽  
M. Sun
Keyword(s):  
Underwater Explosion ◽  
Water Jet ◽  
Bubble Collapse ◽  
Rectangular Tube

scholarly journals The Fluid-Solid Interaction Dynamics between Underwater Explosion Bubble and Corrugated Sandwich Plate

2016 ◽  
Vol 2016 ◽  
pp. 1-21
Author(s):  
Hao Wang ◽  
Yuan Sheng Cheng ◽  
Jun Liu ◽  
Lin Gan
Keyword(s):  
Shock Wave ◽  
Failure Modes ◽  
Sandwich Structures ◽  
Numerical Models ◽  
Near Field ◽  
Three Dimensional ◽  
Underwater Explosion ◽  
Bubble Collapse ◽  
Fe Model ◽  
Wave Load

Lightweight sandwich structures with highly porous 2D cores or 3D (three-dimensional) periodic cores can effectively withstand underwater explosion load. In most of the previous studies of sandwich structure antiblast dynamics, the underwater explosion (UNDEX) bubble phase was neglected. As the UNDEX bubble load is one of the severest damage sources that may lead to structure large plastic deformation and crevasses failure, the failure mechanisms of sandwich structures might not be accurate if only shock wave is considered. In this paper, detailed 3D finite element (FE) numerical models of UNDEX bubble-LCSP (lightweight corrugated sandwich plates) interaction are developed by using MSC.Dytran. Upon the validated FE model, the bubble shape, impact pressure, and fluid field velocities for different stand-off distances are studied. Based on numerical results, the failure modes of LCSP and the whole damage process are obtained. It is demonstrated that the UNDEX bubble collapse jet local load plays a more significant role than the UNDEX shock wave load especially in near-field underwater explosion.

Prediction of Residual Stress Improvement by Water Jet Peening Using Cavitating Jet Simulation With Bubble Flow Model

2010 ◽  
Author(s):  
Masashi Fukaya ◽  
Ren Morinaka ◽  
Noboru Saitou ◽  
Hisamitsu Hatou ◽  
Yoshiaki Tamura ◽  
...  
Keyword(s):  
Residual Stress ◽  
Flat Plate ◽  
Power Plants ◽  
Compressive Residual Stress ◽  
Flow Model ◽  
Water Jet ◽  
Bubble Collapse ◽  
Bubble Flow ◽  
Bubble Pressure ◽  
Cavitating Jet

We developed the new method for predicting a region of compressive residual stress on the weld surface after water jet peeing (WJP), which is a preventive maintenance technology for nuclear power plants. A cavitating jet is impinged on the weld surfaces of structures in a nuclear reactor. Bubble collapse impact causes plastic deformation of the weld surface, and changes the residual stress from tensile to compressive. Compressive residual stress prevents the occurrence of stress corrosion cracking (SCC) on the weld surface. A cavitating jet vertically injected into a submerged flat plate was investigated. Tensile stress was introduced onto the surface of the stainless steel plate by grinding before WJP in the experiment. We numerically simulated impulsive bubble pressure that varied by microseconds in the cavitating jet with the “bubble flow model”. The bubble flow model simulates the abrupt time-variations in the radius and inner pressure of bubbles based on the Rayleigh-Plesset equation in a cavitating flow. The cavitation collapse energy was estimated based on the bubble pressure. The cavitation collapse energy was compared with the measured compressive residual stress on the flat plate after WJP. The radial range of the compressive residual stress from the jet center axis is one of the most important measures of performance of WJP. The radial range of the cavitation collapse energy corresponded to that of compressive residual stress with a prediction error of +/− 20% under different conditions of jet velocity and the distance between the jet nozzle and plate surface. The results confirmed that the method we developed for predicting the region of compressive residual stress after WJP was valid.

Cavitation desulfurization in vulcanized rubber recycling under ultra-high pressure water jet

2017 ◽  
Vol 37 (5) ◽  
pp. 529-536
Author(s):  
Shouxu Song ◽  
Hui Zha ◽  
Haihong Huang
Keyword(s):  
High Pressure ◽  
Water Jet ◽  
Bubble Collapse ◽  
Infrared Spectrometry ◽  
Rubber Powder ◽  
Ultra High Pressure ◽  
Vulcanized Rubber ◽  
Gel Fraction ◽  
Pressure Water ◽  
High Pressure Water Jet

Abstract Ultra-high pressure water jet is proposed for recycling of vulcanized waste rubber, and cavitation desulfurization in the recycling process is analyzed. The chemical effects of mechanical shearing, pyrolysis, free radical oxidation, and supercritical oxidation produced by bubble collapse are considered the main causes of desulfurization. Scanning electron microscopy, Fourier transform infrared spectrometry, differential scanning calorimetry, nuclear magnetic resonance test, and X-ray photoelectron spectroscopy are used to determine the performance of rubber powder. Gel fraction of rubber powder is measured to analyze the effect of jet pressure on desulfurization. Results indicate that the vulcanized rubber could achieve partial desulfurization. The glass transition temperature of the rubber powder slightly increases after crushing. With the increase of jet pressure, the gel fraction of rubber powder initially decreases and then increases, as well as achieves a minimum value at the jet pressure of nearly 220 MPa, which is ideal for desulfurization.

A Numerical Study of Underwater Explosion Bubble

2013 ◽  
Vol 706-708 ◽  
pp. 1734-1737
Author(s):  
Cho Chung Liang ◽  
Tso Liang Teng ◽  
Ching Yu Hsu ◽  
Anh Tu Nguyen
Keyword(s):  
Numerical Study ◽  
Underwater Explosion ◽  
Water Jet ◽  
Dynamical Process ◽  
Floating Structures ◽  
Jet Impact ◽  
Long Time ◽  
Bubble Pulsation ◽  
Short Time ◽  
Collapse Phase

The dynamical process of underwater explosion bubble is a very complicated phenomenon with many facets needed to consider. After detonation, shock wave propagates in a very short time while the oscillation of bubble occurs in a long time. Bubble pulsation can cause serious damage for the structures nearby due to the whipping effect, bubble pulse or water jet impact in the collapse phase. This paper presents an application of Finite Element Method (FEM), namely Eulerian technique, to simulate the dynamical process of bubble and numerical results were verified by an experiment. This approach shows it's feasibility in simulating the bubble pulsation as well as the formation of water jet at the end of first contracting circle. Although numerical model was simplified by the boundary conditions, the success of this method is foundation for further study of bubble such as in predicting the damages of both nearby submerged structures as well as floating structures.

Numerical research of water jet characteristics in underwater explosion based on compressible multicomponent flows

2021 ◽  
Vol 242 ◽  
pp. 110135
Author(s):  
Jun Yu ◽  
Jianhu Liu ◽  
Bin He ◽  
Haitao Li ◽  
Teng Xie ◽  
...  
Keyword(s):  
Underwater Explosion ◽  
Water Jet ◽  
Multicomponent Flows ◽  
Numerical Research ◽  
Jet Characteristics

Transient Response of the Steel Plate to Underwater Explosion Bubble

2020 ◽  
Author(s):  
Yingyu Chen ◽  
Xiongliang Yao ◽  
Liangtao Liu ◽  
Ning Gan ◽  
Xiongwei Cui
Keyword(s):  
Dynamic Response ◽  
Physical Process ◽  
Bubble Growth ◽  
Steel Plate ◽  
Permanent Deformation ◽  
Three Dimensional ◽  
Underwater Explosion ◽  
Complex Problem ◽  
Bubble Collapse ◽  
The Finite Element Method

Abstract In this paper, a coupling eulerian langarian method (CEL) is used to study the interaction between a collapsing underwater explosion bubble and a steel plate. The VOF method is used to simulate the physical process of bubble growth, contraction and collapse, while the finite element method is used to calculate dynamic response of the steel plate. By establishing the three dimensional numerical model, the study reveals the interesting insights into the complex problem of interaction a underwater explosion bubble and a steel plate, including the physical process of bubble growth, contraction and collapse, the dynamic response of the steel plate, as well as the wall pressure induced by the bubble dynamic. The results indicate that the elastic-plastic plate will generate permanent deformation loaded by the water jet; owing to the deformation of the nearby structure, the bubble shows as a “hazel” in the bubble contraction phase and forms toroidal jet which leads the bubble into several toroidal bubbles in the bubble collapse phase. This paper aim at proposing an effective numerical method which can be useful for the problem of strong interaction between bubble and structure.

scholarly journals Simulation of the Collapse of an Underwater Explosion Bubble under a Circular Plate

2005 ◽  
Vol 12 (3) ◽  
pp. 217-225 ◽  
Author(s):  
Kit-Keung Kan ◽  
James H. Stuhmiller ◽  
Philemon C. Chan
Keyword(s):  
Hydraulic Jump ◽  
Underwater Explosion ◽  
Complex Interaction ◽  
Bubble Collapse ◽  
Toroidal Bubble ◽  
Jet Impact ◽  
Advection Term ◽  
Two Fluid ◽  
Insight Into ◽  
Good Agreement

A two-fluid, computational fluid dynamics study of the phenomena of bubble collapse under a submersed flat plate has been performed. In order to handle the rapidly changing bubble-water interface accurately, second order upwind differencing is used in calculating the advection term. Good agreement with experimental data is obtained for the pressure distribution on the plate. The computational results provide insight into the phenomenology of the jet impact, the formation of a radial hydraulic jump, and the complex interaction of that hydraulic jump with the collapsing toroidal bubble.

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