scholarly journals Analysis of Blast Wave Parameters Depending on Air Mesh Size

2018 ◽  
Vol 2018 ◽  
pp. 1-18 ◽  
Author(s):  
Hrvoje Draganić ◽  
Damir Varevac
Keyword(s):  
Numerical Simulations ◽  
Blast Wave ◽  
Large Scale ◽  
Wave Interaction ◽  
Mesh Size ◽  
Blast Waves ◽  
3D Environment ◽  
Close Range ◽  
Blast Wave Propagation ◽  
Optimal Mesh

Results of numerical simulations of explosion events greatly depend on the mesh size. Since these simulations demand large amounts of processing time, it is necessary to identify an optimal mesh size that will speed up the calculation and give adequate results. To obtain optimal mesh sizes for further large-scale numerical simulations of blast wave interactions with overpasses, mesh size convergence tests were conducted for incident and reflected blast waves for close range bursts (up to 5 m). Ansys Autodyn hydrocode software was used for blast modelling in axisymmetric environment for incident pressures and in a 3D environment for reflected pressures. In the axisymmetric environment only the blast wave propagation through the air was considered, and in 3D environment blast wave interaction and reflection of a rigid surface were considered. Analysis showed that numerical results greatly depend on the mesh size and Richardson extrapolation was used for extrapolating optimal mesh size for considered blast scenarios.

Blast Wave Mitigation from the Straight Tube by Using Water Part II - Numerical Simulation

2018 ◽  
Vol 910 ◽  
pp. 78-83 ◽  
Author(s):  
Yuta Sugiyama ◽  
Tomotaka Homae ◽  
Kunihiko Wakabayashi ◽  
Tomoharu Matsumura ◽  
Yoshio Nakayama
Keyword(s):  
Experimental Data ◽  
Numerical Simulation ◽  
Energy Transfer ◽  
Numerical Simulations ◽  
Blast Wave ◽  
Blast Waves ◽  
Straight Tube ◽  
Water Interface ◽  
Effect Of Water ◽  
Air Water Interface

This paper investigates explosions in a straight square tube in order to understand the mitigation effect of water on blast waves that emerge outside. Numerical simulations are used to assess the effect of water that is put inside the tube. The water reduces the peak overpressure outside, which agrees well with the experimental data. The increases in the kinetic and internal energies of the water are estimated, and the internal energy transfer at the air/water interface is shown to be an important factor in mitigating the blast wave in the present numerical method.

scholarly journals Improving Accuracy of Coarse Grid Numerical Solution of Solid-Solid Reactions by Taylor Series Expansion of the Reaction Term

2009 ◽  
Vol 2009 ◽  
pp. 1-13
Author(s):  
Hassan Hassanzadeh ◽  
Mehran Pooladi-Darvish ◽  
Jalal Abedi
Keyword(s):  
Numerical Simulations ◽  
Series Expansion ◽  
Taylor Series ◽  
Large Scale ◽  
Mesh Size ◽  
Taylor Series Expansion ◽  
Computational Time ◽  
Time Saving ◽  
Reaction Term ◽  
Reaction Fronts

Exothermic solid-solid reactions lead to sharp reaction fronts that cannot be captured by coarse spatial mesh size numerical simulations that are often required for large-scale simulations. We present a coarse-scale formulation with high accuracy by using a Taylor series expansion of the reaction term. Results show that such expansion could adequately maintain the accuracy of fine-scale behavior of a constant pattern reaction front while using a smaller number of numerical grid cells. Results for a one-dimensional solid-solid reacting system reveal reasonable computational time saving. The presented formulation improves our capabilities for conducting fast and accurate numerical simulations of industrial-scale solid-solid reactions.

Dynamic Response of RC Structures Subjected to Blast Wave Shock Loading

2012 ◽  
Author(s):  
Oruba Rabie ◽  
Yahia M. Al-Smadi
Keyword(s):  
Blast Wave ◽  
Blast Waves ◽  
Charge Weight ◽  
Structural Components ◽  
Reinforced Concrete Column ◽  
Safety Criterion ◽  
Rc Structures ◽  
The Past ◽  
Blast Wave Propagation ◽  
The Stability

The collapse of significant structures caused by terrorist attacks in the past decades has motivated engineers to study the stability of current structural systems and their susceptibility to collapse. This collapse usually occurs due to blast waves generated by the high explosive bursts in the air that hit the structural components of the buildings leading to catastrophic damages which unfortunately happen before the evacuation. In an effort to find a safety criterion for buildings subjected to blasting; this study uses the nonlinear FEA explicit software LS-DYNA to highlight the effect of blast wave propagation on reinforced concrete column taking into account the standoff distance and charge weight variations. The effects of these two variables have been quantified through the comparison of resulted pressures, displacement and impulses.

Experimental and Numerical Investigation of Blast Wave Interaction With a Three Level Building

2017 ◽  
Vol 139 (11) ◽  
Author(s):  
Jacques Massoni ◽  
Laurent Biamino ◽  
Georges Jourdan ◽  
Ozer Igra ◽  
Lazhar Houas
Keyword(s):  
Shock Tube ◽  
Blast Wave ◽  
Wave Interaction ◽  
Wave Pattern ◽  
Blast Waves ◽  
Building Model ◽  
Experimental Part ◽  
Level Building ◽  
Blast Wave Interaction ◽  
Good Agreement

The present work shows that weak blast waves that are considered as being harmless can turn to become fatal upon their reflections from walls and corners inside a building. In the experimental part, weak blast waves were generated by using an open-end shock tube. A three level building model was placed in vicinity to the open-end of the used shock tube. The evolved wave pattern inside the building rooms was recorded by a sequence of schlieren photographs; also pressure histories were recorded on the rooms' walls. In addition, numerical simulations of the evolved flow field inside the building were conducted. The good agreement obtained between numerical and experimental results shows the potential of the used code for identifying safe and dangerous places inside the building rooms penetrated by the weak blast wave.

Numerical Simulations of Blast Wave Propagation Induced by Eruptions of Volcanoes

1995 ◽  
pp. 385-390 ◽  
Author(s):  
T. Saito ◽  
T. Kitamura ◽  
K. Takayama ◽  
N. Fujii ◽  
H. Taniguchi
Keyword(s):  
Wave Propagation ◽  
Numerical Simulations ◽  
Blast Wave ◽  
Blast Wave Propagation

scholarly journals Numerical Analysis of the Blast Wave Propagation due to Various Explosive Charges

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Lucia Figuli ◽  
Damjan Cekerevac ◽  
Chiara Bedon ◽  
Bohuš Leitner
Keyword(s):  
Wave Propagation ◽  
Numerical Analysis ◽  
Blast Wave ◽  
Control Point ◽  
Blast Waves ◽  
Size Type ◽  
Explosive Charges ◽  
Blast Wave Propagation ◽  
Comparative Results ◽  
Basic Features

Blast events and scenarios, as known, represent extreme phenomena that may result in catastrophic consequences, both for humans and structures. Accordingly, for engineering applications, the reliable description of expected blast waves is a crucial step of the overall design process. Compared to ideal theoretical formulations, however, real explosive events can be strongly sensitive to a multitude of parameters and first of all to the basic features (size, type, shape, etc.) of the charge. In this regard, several advanced computer codes can be used in support of design and research developments. Besides, the input parameters and solving assumptions of refined numerical methods are often available and calibrated in the literature for specific configurations only. In this paper, with the support of the ANSYS Autodyn program, special care is dedicated to the numerical analysis of the blast wave propagation in the air due to several charges. Five different explosives are taken into account in this study, including RDX, DAP-2, DAP-E, Polonit-V, and homemade ANFO. The effects of different mixtures are thus emphasized in terms of the predicted blast wave, as a function of a given control point, direction, explosive mass, and composition. As shown, relatively scattered peak pressure estimates are collected for a given explosive. Comparative results are hence proposed towards selected experimental data of the literature, as well as based on simple analytical predictions. The collected overpressure peak values are thus discussed for the selected explosive charges.

Numerical Simulation of Blast-Wave Propagation in a Small Two-Medium Duct

2009 ◽  
Vol 25 (3) ◽  
pp. 313-322 ◽  
Author(s):  
S.-M. Liang ◽  
J.-C. Yuan
Keyword(s):  
Wave Propagation ◽  
High Resolution ◽  
Blast Wave ◽  
Equations Of State ◽  
Blast Waves ◽  
Weno Scheme ◽  
Navier Stokes ◽  
Viscous Effects ◽  
Resolution Scheme ◽  
Blast Wave Propagation

AbstractIn this study, a small two-medium duct with blast-wave propagation is numerically investigated by a high-resolution Euler/Navier-Stokes solver. The solver has a feature of treatment of the Tait equations of state for two media. One of the two media is water which is envisaged as a blood. The second medium is another liquid, used to simulate body's clot or tissue. The duct wall has a mass diffusion effect in addition to viscous effects. Since two different media are considered, the reflection and transmission of an underwater blast wave passing through the interfaces of the two media with different sound impedances are inevitable. The different properties of liquids may cause numerical oscillation at interfaces for very weak blast waves for a high-resolution scheme such as a 5th-order WENO scheme. In order to overcome this difficulty of numerical fictitious oscillation, a third-order WENO scheme was used. It was found that computed pressures of the transmitted blast wave for four kinds of simulated tissues are in good agreements with those obtained by the acoustic principle. Moreover, for the case of a simulated clot, the pressure force and impulse acted on the clot surface are investigated for different intensities of blast waves.

scholarly journals Numerical Method for Predicting the Blast Wave in Partially Confined Chamber

2018 ◽  
Vol 2018 ◽  
pp. 1-17 ◽  
Author(s):  
Wei-zheng Xu ◽  
Xiang-shao Kong ◽  
Cheng Zheng ◽  
Wei-guo Wu
Keyword(s):  
Blast Wave ◽  
Mach Reflection ◽  
Wave Interaction ◽  
Experimental Tests ◽  
Blast Waves ◽  
Finite Difference Schemes ◽  
Test Problems ◽  
Confined Space ◽  
Weighted Essentially Nonoscillatory ◽  
Fifth Order

Blast waves generated by cylindrical TNT explosives in partially confined chamber were studied numerically and experimentally. Based on the classical fifth-order weighted essentially nonoscillatory finite difference schemes (fifth-order WENO schemes), the 1D, 2D, and 3D codes for predicting the evolution of shock waves were developed. A variety of benchmark-test problems, including shock tube problem, interacting blast wave, shock entropy wave interaction, and double Mach reflection, were studied. Experimental tests of explosion events in a partially confined chamber were conducted. Then, the 3D code was employed to predict the overpressure-time histories of certain points of chamber walls. Through comparing, a good agreement between numerical prediction and experimental results was achieved. The studies in this paper provide a reliable means to predict the blast load in confined space.

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