Dynamics of an Underwater Explosion Bubble near a Rigid Wall: Effect of Slenderness Ratio, Installation, and Distance Parameter

2017 ◽  
Vol 33 (4) ◽  
pp. 959-971 ◽  
Author(s):  
Zhifan Zhang ◽  
Longkan Wang ◽  
Xiongliang Yao ◽  
Jicai Lang
Keyword(s):  
Slenderness Ratio ◽  
Underwater Explosion ◽  
Rigid Wall ◽  
Wall Effect ◽  
Distance Parameter

scholarly journals SPH-BEM simulation of underwater explosion and bubble dynamics near rigid wall

2019 ◽  
Vol 62 (7) ◽  
pp. 1082-1093 ◽  
Author(s):  
ZhiFan Zhang ◽  
Cheng Wang ◽  
A-Man Zhang ◽  
Vadim V Silberschmidt ◽  
LongKan Wang
Keyword(s):  
Bubble Dynamics ◽  
Underwater Explosion ◽  
Rigid Wall

Wall effect of underwater explosion load based on wave motion theories

2014 ◽  
Vol 28 (5) ◽  
pp. 587-598 ◽  
Author(s):  
Wei Xiao ◽  
Xiong-liang Yao ◽  
Jun Guo
Keyword(s):  
Wave Motion ◽  
Underwater Explosion ◽  
Wall Effect ◽  
Explosion Load

The Application of CEL Technique to Simulate the Behavior of an Underwater Explosion Bubble in the Vicinity of a Rigid Wall

2020 ◽  
Vol 902 ◽  
pp. 126-139
Author(s):  
Anh Tu Nguyen
Keyword(s):  
Finite Element ◽  
High Speed ◽  
Bubble Dynamics ◽  
Underwater Explosion ◽  
Flow Simulation ◽  
Rigid Wall ◽  
Water Jet ◽  
Complex Structures ◽  
Explicit Finite Element ◽  
Jet Impact

The dynamic process of an underwater explosion (UNDEX) is a complex phenomenon that involves several facets. After detonation, the shockwave radially propagates at a high speed and strikes nearby structures. Subsequently, bubble oscillation may substantially damage the structures because of the whipping effect, water jet impact, and bubble pulse. This paper presents an application of explicit finite element analyses to simulate the process of an UNDEX bubble in the vicinity of rigid wall, in which the coupled Eulerian-Lagrangian (CEL) approach was developed to overcome the difficulties regarding the classical finite element method (FEM), large deformations, and flow simulation of fluid and gas. The results demonstrate that the method is well suited to manage the UNDEX bubble problem and can be used to model the major features of the bubble dynamics. Furthermore, the behavior of an UNDEX bubble near a rigid wall was also examined in the present study, which showed that the migration of the bubble and the development of the water jet are influenced strongly by the standoff distance between the initial bubble position and the wall. This method can be used in future studies to examine UNDEX bubbles in the vicinity of deformable and complex structures.

Dynamic Behavior of Bubble near Vertical Plate in Underwater Explosion

2011 ◽  
Vol 52-54 ◽  
pp. 1080-1085
Author(s):  
Jian Li ◽  
Ji Li Rong ◽  
Da Lin Xiang
Keyword(s):  
Dynamic Behavior ◽  
Vertical Plate ◽  
Underwater Explosion ◽  
Rigid Wall ◽  
Engineering Calculation ◽  
Initial Condition ◽  
Bubble Motion ◽  
Fluid Field ◽  
Acceleration Model ◽  
Theory Research

In this study, the volume-acceleration model was introduced to determine the initial condition for bubble motion during underwater explosion. Subroutines, which defined the initial and boundary conditions of the fluid field, were developed based on MSC.DYTTAN software. Numerical simulations were compared with the results of validated experimental data. From the basic phenomenon of interaction between a bubble and a vertical rigid wall, the dynamic behavior of a bubble near a vertical rigid wall was simulated and analyzed. The dynamic behavior of bubble and the jet were studied systematically and summarized relative to the law that both of the motion of bubble and water jet are closely related with the standoff distance parameter. The results of this study have valuable implications for correlative theory research and engineering calculation.

scholarly journals AiStudy on the Behavior of an Underwater Explosion Bubble near a Rigid Wall

2021 ◽  
Vol 9 ◽  
Author(s):  
Ching-Yu Hsu ◽  
◽  
Cho-Chung Liang ◽  
Vo-Phuong Duy ◽  
◽  
...  
Keyword(s):  
High Pressure ◽  
Free Field ◽  
Underwater Explosion ◽  
Flow Simulation ◽  
Rigid Wall ◽  
Complex Structures ◽  
High Expectations ◽  
Jet Impact ◽  
Bubble Interaction ◽  
Explosive Charges

The dynamic approach to an underwater explosion (UNDEX) is a complex episode that involves shockwave propagation, bubble pulse with high pressure, and water jet impact. This paper proposes linkage of Finite Element Avenue (FEM) and Companion of Eulerian-Lagrangian (CEL) to supply promised data of large deformations and flow simulation of fluid and gas where the bubble interaction is near a stiff wall. To conduct the process, a 7.5 m x 9.0 m Eulerian domain and explosive charges of 10 g, 35 g, and 55 g TNT are built in a free field, respectively. Numerical analysis, as far as a comparison with research from E. Klaseboer, has been given in this study. The important results obtained from the CEL approach imply high expectations. In spite of the fact that this approach is not adequately consistent to totally supplant a live test, it can be utilized as an outline database to anticipate outcomes of managing an UNDEX with a high pressure bubble. The behavioral explosion from an UNDEX bubble near a rigid wall is a prospective contribution in this research. With these results, this technique can be used in further studies to examine UNDEX bubbles in the vicinity of deformable and complex structures.

Electrophoretic motion of an arbitrary prolate body of revolution toward an infinite conducting wall

1994 ◽  
Vol 264 ◽  
pp. 41-58 ◽  
Author(s):  
Jian-Jun Feng ◽  
Wang-YI WU
Keyword(s):  
Boundary Conditions ◽  
Slenderness Ratio ◽  
Prolate Spheroid ◽  
Wall Effect ◽  
Curvature Radius ◽  
Hydrodynamic Equations ◽  
Body Of Revolution ◽  
Linear Algebraic Equations ◽  
Planar Wall ◽  
Infinite Planar

The electrophoretic motion of an arbitrary prolate body of revolution perpendicular to an infinite conducting planar wall is investigated by a combined analytical–numerical method. The electric field is exerted normal to the conducting planar wall and parallel to the axis of revolution of the particle. The governing equations and boundary conditions are obtained under the assumption of electric double layer thin compared to the local particle curvature radius and the spacing between the particle and the boundary. The axisymmetrical electrostatic and hydrodynamic equations are solved by the method of distribution of singularities along a certain line segment on the axis of revolution inside the particle. The analytical expressions for fundamental singularities both of electrostatic and hydrodynamic equations in the presence of the infinite planar wall are derived. Employing a piecewise parabolic approximation for the density function and applying the boundary collocation method to satisfy the boundary conditions on the surface of the particle, a system of linear algebraic equations is obtained which can be solved by matrix reduction technique.Solutions for the electrophoretic velocity of the colloidal prolate spheroid are presented for various values of a/b and a/d, where a and b are the major and minor axes of the particle respectively and d is the distance between the centre and the wall. Numerical tests show that convergence to at least four digits can be achieved. For the limiting cases of a = b or d→ ∞, our results agree quite well with the exact solutions of electrophoresis of a sphere moving perpendicularly to an infinite planar wall or of a prolate spheroid in an unbounded fluid. As expected, owing to the effect of the wall, the electrophoretic mobility of the particle decreases monotonically for a given spheroid as it gets closer to the wall. Another important feature is that the wall effect on electrophoresis will reduce with the increase of slenderness ratio of the prolate spheroid at the same value of a/d. The boundary effect on the particle mobility and flow pattern in electrophoresis differ significantly from those of the corresponding sedimentation problem and the wall effect on the electrophoresis is much weaker than that on the sedimentation. In order to demonstrate the generality of the proposed method, the convergent results for prolate Cassini ovals are also given in the present paper.

scholarly journals A Numerical and Experimental Study of Wall Pressure Caused by an Underwater Explosion Bubble

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Yingyu Chen ◽  
Xiongliang Yao ◽  
Xiongwei Cui
Keyword(s):  
High Speed ◽  
Bubble Dynamics ◽  
Numerical Study ◽  
Underwater Explosion ◽  
Rigid Wall ◽  
Numerical Results ◽  
Wall Pressure ◽  
Bubble Collapse ◽  
Strong Impact ◽  
Jet Impact

The bubble dynamics behaviors and the pressure in the wall center are investigated through experimental method and numerical study. In the experiment, the dynamics of an underwater explosion (UNDEX) bubble beneath a rigid wall are captured by high-speed camera and the wall pressure in the wall center is measured by pressure transducer. To reveal the process and mechanism of the pressure on a rigid wall during the first bubble collapse, numerical studies based on boundary element method (BIM) are applied. Numerical results with two different stand-off parameters (γ=0.38 and γ=0.90) show excellent agreement with experiment measurements and observations. According to the experimental and the numerical results, we can conclude that the first peak is caused by the reentrant jet impact and the following splashing effect enlarged the duration of the first jet impact. When γ=0.38, the splashing jet has a strong impact on the minimum volume bubble, a number of tiny bubbles, formed like bubble ring, are created and collapse more rapidly owing to the surrounding high pressure and emit multi shock waves. When γ=0.90, the pressure field around the bubble is low enough only a weak rebounding bubble peak occurs.

IDENTIFIKASI RASIO PARAMETER KAPAL PENUMPANG CATAMARAN BERBAHAN FRP

2013 ◽  
Vol 12 (3) ◽  
Author(s):  
Soegeng Hardjono
Keyword(s):  
Main Parameter ◽  
Slenderness Ratio ◽  
Technical Analysis ◽  
Preliminary Design ◽  
Naval Architecture

Parameter ratios are important information for the ship designer in the preliminary design stages. They can be used as a tool to identify the main parameter of vessel and their other technical characteristics. The information about parameter ratios of mono-hull vessel is currently available in Naval Architecture literatures, but it is not the case for the type of twin-hull vessel called catamaran. Having conducted technical analysis in this research, it has been identified that parameter ratios of passenger catamaran vessel made of FRP has values of L / B ratio from 2.52 up to 3.7, L / D ratio from 5.25 up to 11:24, slenderness ratio (Lwl/BwL) from  9 up to 12. Other values of various parameter ratios like B/T, D/T, L /√ L, and Displacement/L are also discussed.

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