Investigation of bubble dynamics of underwater explosion based on improved compressible numerical model

2016 ◽  
Vol 59 ◽  
pp. 472-482 ◽  
Author(s):  
W. Xiao ◽  
A.M. Zhang ◽  
S.P. Wang
Keyword(s):  
Numerical Model ◽  
Bubble Dynamics ◽  
Underwater Explosion

Study on the Bubble Dynamics and the Exciting Force in a Bended Pipe Based on BEM

2016 ◽  
Author(s):  
Y. L. Liu ◽  
Z. L. Tian
Keyword(s):  
Numerical Model ◽  
Potential Theory ◽  
Bubble Dynamics ◽  
Flow Speed ◽  
Exciting Force ◽  
Incoming Flow ◽  
Bubble Motion ◽  
Dynamics Model ◽  
Pipe Surface ◽  
Direction Change

Nonlinear bubble dynamics in a pipeline and its exciting force are investigated by a numerical model based on BEM. The bubble motion is one of the main causes that the pipeline vibrates and generates noise in modern ships. The numerical bubble dynamics model is established under the incompressible potential theory. Bubble motion with different incoming flow in a bended pipe is simulated. We found that the bubble develops jet when it passes by the bend, and adjoin to the pipe surface in the side of the fillet center. The pulsation and the direction change of the bubble apply an exciting force on the pipe which has a positive correlation with the incoming flow speed and may lead vibration and noise.

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

A new formulation and analysis of a collapsing bubble with different content in a liquid induced during acoustic cavitation

2016 ◽  
Vol 26 (6) ◽  
pp. 1729-1746
Author(s):  
Ali Alhelfi ◽  
Bengt Ake Sunden
Keyword(s):  
Partial Differential Equations ◽  
Numerical Model ◽  
Differential Equations ◽  
Bubble Dynamics ◽  
Acoustic Cavitation ◽  
Ultrasonic Field ◽  
Bubble Surface ◽  
Correct Prediction ◽  
Partial Differential ◽  
Content Type

Purpose – The purpose of this paper is to present numerical investigation of the gas/vapor bubble dynamics under the influence of an ultrasonic field to give a more comprehensive understanding of the phenomenon and present new results Design/methodology/approach – In order to formulate the mathematical model, a set of governing equations for the gas inside the bubble and the liquid surrounding it are used. All hydrodynamics forces acting on the bubble are considered in the typical solution. The systems of equations required to be solved consist of ordinary and partial differential equations, which are both nonlinear and time dependent equations. A fourth order Runge-Kutta method is applied to solve the ordinary differential equations. On the other hand, the finite difference method is employed to solve the partial differential equations and a time-marching technique is applied. Findings – The numerical model which is developed in the current study permits a correct prediction of the bubble behavior and its characteristics in an acoustic field generated at this occasion. Originality/value – Previous studies considering numerical simulations of an acoustic bubble were performed based on the polytropic approximation or pressure uniformity models of the contents inside the bubble. In this study, an enhanced numerical model is developed to study the acoustic cavitation phenomenon and the enhancement concerns taking into account both the pressure and temperature gradients inside the bubble as well as heat transfer through the bubble surface into account which is very important to obtain the temperature of the liquid surrounding the bubble surface.

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.

Experimental and Numerical Investigation of Reinforced Concrete Pile Subjected to Near-Field Non-Contact Underwater Explosion

2020 ◽  
Vol 20 (06) ◽  
pp. 2040003
Author(s):  
Qiushi Yan ◽  
Chen Liu ◽  
Jun Wu ◽  
Jun Wu ◽  
Tieshuan Zhuang
Keyword(s):  
Reinforced Concrete ◽  
Numerical Model ◽  
Failure Mode ◽  
Numerical Study ◽  
Lateral Displacement ◽  
Near Field ◽  
Concrete Strength ◽  
Underwater Explosion ◽  
Load Bearing ◽  
Damage Pattern

High-pile wharf is an important port structure and may suffer from accidental explosions or terrorist bombing attack during the service life. The reinforced concrete (RC) pile is one of the popular vertical load-bearing piles of high-pile wharf structure. As a main load-bearing member of the high-pile wharf structure, the damage of RC pile due to underwater explosive may cause subsequently progressive collapse of the whole structure. In this paper, the dynamic response and failure mode of RC pile in high-pile wharf structure under the near-field non-contact underwater explosion are investigated using a combined experimental and numerical study. First, a typical RC pile was designed and tested for the near-field non-contact underwater explosion. The failure mode and damage of the RC pile specimen were obtained and analyzed. Second, the numerical model of the RC pile under near-field non-contact underwater explosion was established by adopting the commercial software AUTODYN, and then validated based on experimental results. It was shown that the results from numerical model and experimental test compared very well in terms of the damage pattern and lateral displacement. Furthermore, the full-scale numerical model of the RC pile for the near-field non-contact underwater explosion was developed based on the validated numerical model to investigate the damage pattern and failure mode of RC pile under varied underwater explosives. Lastly, the safety distance for the RC pile for the underwater explosion loading with consideration of different explosive mass, the explosive depth and the concrete strength was suggested. The outcome of this study presented reference for analysis, assessment and design of the type of RC pile for high-pile wharf structure subjected to near-field non-contact underwater explosion.

scholarly journals Spherical Solutions of an Underwater Explosion Bubble

1998 ◽  
Vol 5 (2) ◽  
pp. 89-102 ◽  
Author(s):  
Andrew B. Wardlaw ◽  
Hans U. Mair
Keyword(s):  
Experimental Data ◽  
Flow Field ◽  
Euler Equations ◽  
Model Comparison ◽  
Bubble Dynamics ◽  
Water Solution ◽  
Fluid Motion ◽  
Underwater Explosion ◽  
Bubble Flow ◽  
Insight Into

The evolution of the 1D explosion bubble flow field out to the first bubble minimum is examined in detail using four different models. The most detailed is based on the Euler equations and accounts for the internal bubble fluid motion, while the simplest links a potential water solution to a stationary, Isentropic bubble model. Comparison of the different models with experimental data provides insight into the influence of compressibility and internal bubble dynamics on the behavior of the explosion bubble.

Sign in / Sign up

Export Citation Format

Share Document