Modeling of the whole process of shock wave overpressure of free-field air explosion

In this paper, we describe the development and validation of a simulation based methodology for predicting centrifugal impeller rotor locked noise generated at supersonic relative tip speeds when shock waves dominate the acoustic field. Propagating shock waves were calculated in the compressor inlet with a RANS code using an acoustic quality grid to track the sound power as the shocks transition from non-linear to linear propagating wavefronts. The predicted shocks were compared with unsteady pressure measurements obtained from sensors installed on the impeller shroud wall as part of the validation procedure. Calculated shock signatures compared well with the directly measured pressure field propagating over the shroud wall. An independent measurement of acoustic power was also conducted in the free field outside of the test cell. The predicted acoustic power compared within 1dB of the direct measurement validating the simulation based methodology for centrifugal impeller rotor locked shock noise. The resulting study provides both prediction and measurement of the generation, evolution, and far field acoustic power of centrifugal impeller blade passage shock wave noise.

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Experimental Study on the Damage Characteristics of Polymer Slabs Subjected to Air Contact and Close-In Explosions

Advances in Materials Science and Engineering ◽

10.1155/2021/2825062 ◽

2021 ◽

Vol 2021 ◽

pp. 1-14

Author(s):

Zhidong Liu ◽

Xiaohua Zhao ◽

Hongyuan Fang ◽

Xueming Du ◽

Binghan Xue ◽

...

Keyword(s):

Mechanical Properties ◽

Shock Wave ◽

Failure Mode ◽

Explosive Charge ◽

Time History ◽

Dynamic Mechanical Properties ◽

Charge Weight ◽

Pressure Time ◽

Static Mechanical ◽

Air Explosion

As a new antiseepage reinforcement material, polyurethane grouting material has been widely studied in terms of its static mechanical properties. However, research on its dynamic mechanical properties is relatively rare. In this research, considering the influence of the explosive charge weight, the air contact and close-in explosion experiments of polymer slabs were carried out. The failure mode and damage spatial distribution characteristics of polymer slabs were explored. Pressure time history curve of air shock wave was obtained using an air shock wave tester. The influence of polymer slabs on the propagation of air explosion shock wave was compared and analyzed. The results show that, under the air contact explosion, the polymer slab mainly suffers local damage, while under close-in explosion, overall damage is the main damage mode. With the increase of the explosive charge weight, the failure mode of the polymer slab transits from surface crack and slight spalling to local and whole crushing.

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Numerical Investigation of Rockburst Effect of Shock Wave on Underground Roadway

Shock and Vibration ◽

10.1155/2015/867582 ◽

2015 ◽

Vol 2015 ◽

pp. 1-10 ◽

Cited By ~ 7

Author(s):

Cai-Ping Lu ◽

Guang-Jian Liu ◽

Hong-Yu Wang ◽

Jun-Hua Xue

Keyword(s):

Shock Wave ◽

Simulation Software ◽

Vibration Source ◽

Whole Process ◽

Working Face ◽

Mining Conditions ◽

Coal Rock ◽

Mining Coal ◽

And Control ◽

Attenuation Characteristics

Using UDEC discrete element numerical simulation software and a cosine wave as vibration source, the whole process of rockburst failure and the propagation and attenuation characteristics of shock wave in coal-rock medium were investigated in detail based on the geological and mining conditions of 1111(1) working face at Zhuji coal mine. Simultaneously, by changing the thickness and strength of immediate roof overlying the mining coal seam, the whole process of rockburst failure of roadway and the attenuation properties of shock wave were understood clearly. The presented conclusions can provide some important references to prevent and control rockburst hazards triggered by shock wave interferences in deep coal mines.

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Effects of Explosion Shock Waves on Lung Injuries in Rabbits

Shock and Vibration ◽

10.1155/2021/6676244 ◽

2021 ◽

Vol 2021 ◽

pp. 1-10

Author(s):

Yanlong Sun ◽

Xinming Qian ◽

Chi-Min Shu ◽

Ziyuan Li ◽

Mengqi Yuan ◽

...

Keyword(s):

Shock Wave ◽

Shock Waves ◽

Free Field ◽

Damage Mechanism ◽

Injury Mechanism ◽

Severe Injury ◽

Severe Injuries ◽

Lung Injuries ◽

Test Points ◽

Hematoxylin Eosin

The purpose of this study was to explore the damage effects and injury mechanism of free-field explosion shock waves on rabbit lungs. Six free-field explosion experiments, each with 500 g trinitrotoluene (TNT), were conducted as the shock wave overpressure acting on the rabbits was measured. The peak overpressure of the shock wave was 533, 390, 249, 102, and 69 kPa at the respective test points. Damage to the rabbit lungs caused by shock wave overpressure was investigated through observation, anatomical analysis, and hematoxylin-eosin (HE) staining processing. The shock wave overpressure of 69–102 kPa caused mild-to-moderate injury; the shock wave overpressure of 102–249 kPa caused moderate injury; the shock wave overpressure of 249–390 kPa resulted in moderate-to-severe injury; and the shock wave overpressure of 390–533 kPa caused severe injury to the rabbit. Mild, moderate, and severe injuries destroyed some, most, or all alveolar structures, correspondingly, as well as producing partial cell apoptosis. The overpressure damage mechanism primarily involves the collapse and rupture of pulmonary alveolus in the lung tissue. As a novel attempt, the investigation provided here may serve to improve the current shock wave injury mechanism.

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Numerical simulation of the front of an air shock wave in a ground and air explosion in the software package LS-DYNA

Structural Mechanics of Engineering Constructions and Buildings ◽

10.22363/1815-5235-2018-14-6-467-474 ◽

2018 ◽

Vol 14 (6) ◽

pp. 467-474 ◽

Cited By ~ 1

Author(s):

O.V. Mkrtychev ◽

◽

A.Y. Savenkov ◽

Keyword(s):

Numerical Simulation ◽

Shock Wave ◽

Software Package ◽

Air Explosion

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Numerical Investigation of Bubble Cloud Dynamics in Shock Wave Lithotripsy

Volume 1: Fora, Parts A and B ◽

10.1115/fedsm2002-31010 ◽

2002 ◽

Cited By ~ 3

Author(s):

Michel Tanguay ◽

Tim Colonius

Keyword(s):

Shock Wave ◽

Shock Wave Lithotripsy ◽

Focal Point ◽

Free Field ◽

Single Pulse ◽

Curvilinear Coordinates ◽

Artificial Kidney ◽

Bubble Cloud ◽

Extracorporeal Shock Wave ◽

Cloud Dynamics

To provide greater understanding of some of the phenomena in Extracorporeal Shock Wave Lithotripsy (ESWL), we implemented a two-phase continuum model for cavitating flow and applied it to the simulation of bubble cloud dynamics in an electro-hydraulic lithotripter. Through the combination of a WENO shock capturing scheme, curvilinear coordinates system and ensemble averaged mixture model, we computed the evolution of the lithotripsy shock wave and the concomitant cavitation field. In this paper, we present the results for three different configurations: a single-pulse lithotripter (free field), a single-pulse lithotripter with rigid artificial kidney stone at the focal point, and a dual-pulse lithotripter. Qualitative and quantitative comparisons of the numerical results to experimental observations are also included.

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Computational simulation of shock wave generated by the detonation of explosives for civil use

MATEC Web of Conferences ◽

10.1051/matecconf/202030500019 ◽

2020 ◽

Vol 305 ◽

pp. 00019

Author(s):

Ligia Ioana Tuhuţ ◽

Emilian Ghicioi

Keyword(s):

Shock Wave ◽

A Priori ◽

Computational Simulation ◽

Free Field ◽

Concrete Surface ◽

Prevention Measures ◽

Explosion Pressure ◽

Computerized Simulation ◽

Freely Suspended ◽

Real Scenario

When conducting a research concerning the propagation of a shock wave generated by the detonation of civil use explosives, the first thing that comes to mind should be if the detonation process takes place in an obstacle-free field, or the area has obstacles such as rocks, metals structures, wood etc, obstacles that can and will influence the final results, the shock wave curve being obturated by it. On one hand, the paper presents the experimental results obtained after the detonation of a freely suspended load, placed at 0.5m above a concrete surface. On the other hand, it compares the values of explosion pressure as shock wave, measured on 4 sensors linearly disposed at the same elevation to the ground, at a distance of 2,3,4 respectively 6 meters from the explosive charge. These values are determined through computerized simulation, using ANSYS AUTODYN software, by virtually reproducing the real scenario. Following the two experiments (real and virtual), one can conclude that computerized simulation proves to be a very useful instrument in an a priori evaluation of hazardous situations/utility of peak values for shock wave, by allowing the user to develop prevention measures/optimization of the analysed processes and also in further investigations

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On models of blast overpressure effects to the thorax

SN Applied Sciences ◽

10.1007/s42452-020-03834-4 ◽

2020 ◽

Vol 2 (12) ◽

Author(s):

Alexander Stottmeister ◽

Malte von Ramin ◽

Johannes M. Schneider

Keyword(s):

Shock Wave ◽

Free Field ◽

Viscoelastic Behavior ◽

Harmonic Oscillators ◽

Blast Overpressure ◽

Lung Injuries ◽

Time Histories ◽

Physical Response ◽

Blast Wave Propagation ◽

The Individual

AbstractShock waves from explosions can cause lethal injuries to humans. Current state-of the-art models for pressure induced lung injuries were typically empirically derived and are only valid for detonations in free-field conditions. In built-up environments, though, pressure–time histories differ significantly from this idealization and not all explosions exhibit detonation characteristics. Hence, those approaches cannot be deployed. However, the actual correlation between dynamic shock wave characteristics and gradual degree of injury have yet to be fully described. In an attempt to characterize the physical response of the human body to complex shock-wave effects, viscoelastic models were developed in the past (Axelsson and Yelverton, in J Trauma Acute Care Surg 40, 31S–37S, 1996; Stuhmiller et al., in J Biomech. 10.1016/0021-9290(95)00039-9, 1996). We discuss those existing modeling approaches especially in view of their viscoelastic behavior and point out drawbacks regarding their response to standard stimuli. Further, we suggest to fully acknowledge the experimentally anticipated viscoelastic behavior of the effective thorax models by using a newly formulated standard model for viscoelastic solids instead of damped harmonic oscillators. Concerning injury assessment, we discuss the individual injury criteria proposed along with existing models pointing out desirable improvements with respect to complex blast situations, e.g. the necessity to account for repeated exposure (criteria with time-memory), and further adaption with respect to nonlinear gas dynamics inside the lung. Finally, we present an improved modeling approach for complex blast overpressure effects to the thorax with few parameters that is more suitable for the characteristics of complex blast wave propagation than other current models.

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Numerical analysis of characteristics of the wind caused by methane-air explosion

Engineering Computations ◽

10.1108/ec-12-2011-0161 ◽

2014 ◽

Vol 31 (3) ◽

pp. 490-500 ◽

Cited By ~ 4

Author(s):

Qi Zhang ◽

Lei Pang ◽

Dachao Lin

Keyword(s):

Shock Wave ◽

Temperature Distribution ◽

Numerical Analysis ◽

High Velocity ◽

Coal Mines ◽

Strong Wind ◽

Content Type ◽

Underground Coal Mines ◽

Other Information ◽

Air Explosion

Purpose – The high-velocity wind caused by a methane-air explosion is one of the important hazardous effects in explosion events of coal mines, and, however, until now it has not been received much attention from scientific works. The paper aims to discuss this issue. Design/methodology/approach – In consideration of the difficulties in observing particle velocities of high-velocity flows, this work presented a study to reveal the regularity during a methane-air explosion happening in the tunnel of coal mine through the numerical analysis approach. Findings – The strong wind caused by a methane-air explosion is a significant hazard and can cause damage in the accidents of methane-air explosion in underground coal mines, especially at structural opening, according to this work. Obtained results show that maximum particle velocity of the high-velocity wind occurs in the outside region of the premixed area, with a peak value of 400∼500 m/s, and the peak velocity of the high-velocity wind decreases exponentially with distance beyond the premixed area. Originality/value – The objective of this work was to examine the effect of wind caused by a methane-air explosion in a tunnel. Other information, such as shock wave and flame and temperature distribution, has been reported in the previous literatures. However, in the accidents of methane-air explosion in underground coal mines, some phenomena (structural opening is destroyed badly) can not be understood by using shock wave and flame and temperature distribution caused by the explosion. The strong wind caused by a methane-air explosion is another significant hazard and can cause damage in the methane-air explosion accidents in underground coal mines, especially at structural opening, according to this work.

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