scholarly journals Numerical Simulations of Shock Wave–driven Chromospheric Jets

2007 ◽  
Vol 666 (2) ◽  
pp. 1277-1283 ◽  
Author(s):  
L. Heggland ◽  
B. De Pontieu ◽  
V. H. Hansteen
Keyword(s):  
Shock Wave ◽  
Numerical Simulations

Theoretical Analysis of a Reactive Reinforcement Method for Cylindrical Explosion-Containment Vessels

2014 ◽  
Vol 137 (1) ◽  
Author(s):  
Sui Yaguang ◽  
Zhang Dezhi ◽  
Tang Shiying ◽  
Li Jie ◽  
Lin Qizhao
Keyword(s):  
Shock Wave ◽  
Theoretical Analysis ◽  
Plastic Strain ◽  
Numerical Simulations ◽  
Circumferential Strain ◽  
Theoretical Calculations ◽  
Practical Application ◽  
Related Research ◽  
Explosion Loading ◽  
Approximate Expressions

A method for cylindrical explosion-containment vessels was presented, which used symmetrical implosion loading cooperating with the vessels to control the out-explosion loading, increasing the anti-explosion ability of explosion-containment vessels. In this study, theoretical analysis was developed first and response of cylindrical vessels loaded with implosion and out-explosion was discussed. Approximate expressions for final circumferential strain were obtained. Comparison between the theoretical calculations and the numerical simulations showed that the proposed method could effectively reduce the plastic strain of cylindrical explosion-containment vessels. The theoretical analysis introduced in this study can provide reference for related research. In addition, problems such as spall and defense of shock wave need to be solved before the presented method could be carried out in practical application.

Investigation on the Shock Control Using Grooved Surface in a Linear Turbine Nozzle

2017 ◽  
Vol 139 (12) ◽  
Author(s):  
Xinguo Lei ◽  
Mingxu Qi ◽  
Harold Sun ◽  
Liangjun Hu
Keyword(s):  
Shock Wave ◽  
Numerical Simulations ◽  
Smooth Surface ◽  
Engine Performance ◽  
Engine Emissions ◽  
Wave Characteristics ◽  
Grooved Surface ◽  
Rotor Stator Interaction ◽  
Nozzle Configuration ◽  
The One

Radial flow variable nozzle turbine (VNT) enables better matching between a turbocharger and engine and can improve the engine performance as well as decrease the engine emissions, especially when the engine works at low-end operation points. With increased nozzle loading, stronger shock wave and clearance leakage flow may be generated and consequently introduces strong rotor–stator interaction between turbine nozzle and rotor, which is a key concern of rotor high-cycle fatigue (HCF) failure. With the purpose of developing a low shock wave intensity turbine nozzle, the influence of grooved vane on the shock wave characteristics is investigated in the present paper. A Schlieren visualization experiment was first carried out on a linear turbine nozzle with smooth surface and the behavior of the shock wave was studied. Numerical simulations were also performed on the turbine nozzle. Guided by the visualization and numerical simulation, grooves were designed on the nozzle surface where the shock wave was originated and numerical simulations were performed to investigate the influence of grooves on the shock wave characteristics. Results indicate that for a smooth nozzle configuration, the intensity of the shock wave increases as the expansion ratios increase, while the onset position is shifted downstream to the nozzle trailing edge. For a nozzle configuration with grooved vane, the position of the shock wave onset is shifted upstream compared to the one with a smooth surface configuration, and the intensity of the shock wave and the static pressure (Ps) distortion at the nozzle vane exit plane are significantly depressed.

Numerical Simulation of Shock Wave Around-Flow in Explosion Test

2013 ◽  
Vol 671-674 ◽  
pp. 1552-1556
Author(s):  
Xin Ming Zhu ◽  
Hao Zhan ◽  
Zhi Gang Jiang
Keyword(s):  
Numerical Simulation ◽  
Shock Wave ◽  
Numerical Simulations ◽  
Front Surface ◽  
Metal Plate ◽  
Thin Metal ◽  
Back Surface ◽  
Explosion Test ◽  
Thin Metal Plate ◽  
Good Agreement

Numerical simulations for tests of thin metal plate against explosion were performed by using models with and without taking into account shock wave around-flow. The results show that the center deflections of plates from numerical simulations are in good agreement with those from experiments, and that the shock wave around-flow can reach the back surface of plate during the shock wave acting on the front surface of plate and interact with the plate response. It is found that the shock wave around-flow has significant effect on the plate response when the scale distance and the size of the plate are small.

Investigation on the Shock Control Using Grooved Surface in a Linear Turbine Nozzle

2017 ◽  
Author(s):  
Xinguo Lei ◽  
Mingxu Qi ◽  
Harold Sun ◽  
Leon Hu
Keyword(s):  
Shock Wave ◽  
Numerical Simulations ◽  
Smooth Surface ◽  
Engine Performance ◽  
Engine Emissions ◽  
Wave Characteristics ◽  
Grooved Surface ◽  
Rotor Stator Interaction ◽  
Nozzle Configuration ◽  
The One

Radial flow Variable Nozzle Turbine (VNT) enables better matching between a turbocharger and engine, and can improve the engine performance as well as decrease the engine emissions, especially when the engine works at low-end operation points. With increased nozzle loading, stronger shock wave and clearance leakage flow may be generated. The shock wave consequently introduces strong rotor-stator interaction between turbine nozzle and impeller, which is also a key concern of impeller high cycle fatigue failure. With the purpose of developing a shock wave free or low shock wave intensity turbine nozzle, the influence of grooved vane on the shock wave characteristics is investigated in present paper. A Schlieren visualization experiment was first carried out on a linear turbine nozzle with smooth surface and the behavior of the shock wave was studied. Numerical simulations were also performed on the turbine nozzle. The predicted shock wave shape, position and intensity were compared against the Schlieren images. Guided by the visualization and numerical simulation, grooves were designed on the nozzle surface where the shock wave was originated and numerical simulations were performed to investigate the influence of grooves on the shock wave characteristics. Results indicate that for a smooth nozzle configuration, the intensity of the shock wave increases as the expansion ratios increase, while the onset position is shifted downstream to the nozzle trailing edge. For a nozzle configuration with grooved vane, the position of the shock wave onset is shifted upstream compared to the one with a smooth surface configuration, and the intensity of the shock wave as well as the static pressure distortion at the nozzle vane exit plane are significantly depressed.

An Investigation on the Properties of Underwater Shock Waves Generated in Underwater Explosions of High Explosives

1997 ◽  
Vol 119 (4) ◽  
pp. 498-502 ◽  
Author(s):  
S. Itoh ◽  
Z. Liu ◽  
Y. Nadamitsu
Keyword(s):  
Shock Wave ◽  
Shock Waves ◽  
Numerical Simulations ◽  
Underwater Explosion ◽  
High Explosives ◽  
Underwater Shock Wave ◽  
Underwater Explosions ◽  
Expansion Test ◽  
Gas Products ◽  
Underwater Shock

A cylinder expansion test for high explosives was carried out to determine JWL parameters. Using the JWL parameters, we carried out numerical simulations of the underwater shock waves generated by the underwater explosion of the high explosives. Our results showed that the behavior of the underwater shock waves at the vicinity of the explosives differs greatly from that far from the explosives. Especially, the strength of the underwater shock wave nearby the explosive rapidly decreases due to the effect of the expansion of the gas products.

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