scholarly journals Investigations of the Aerodynamic Characteristics of the Shock Tubes : Part 4, Aerodynamic Characteristics of Laval Nozzles Installed in a Shock Tube

1972 ◽  
Vol 15 (82) ◽  
pp. 484-491
Author(s):  
Takefumi IKUl ◽  
Kazuyasu MATSUO
Keyword(s):  
Shock Tube ◽  
Aerodynamic Characteristics ◽  
Shock Tubes ◽  
Laval Nozzles

Use of Shock Tubes for Blast Testing

2013 ◽  
Author(s):  
Chong Whang ◽  
Warren Chilton ◽  
Philemon Chan
Keyword(s):  
Shock Wave ◽  
Shock Tube ◽  
Laboratory Method ◽  
Physical Models ◽  
Test Model ◽  
Shock Tubes ◽  
Cfd Simulations ◽  
Data Comparison ◽  
Blast Overpressure ◽  
Blast Testing

A computational fluid dynamics (CFD) study was carried out with data comparison to provide guidance for the control of open shock tube wave expansion to simulate field blast loadings for the conduct of biomechanical blast overpressure tests against surrogate test models. The technique involves the addition of a diffuser to the shock tube to prevent overexpansion before the shock wave impacts the test model. Mild traumatic brain injury (mTBI) has been identified as the signature injury for the conflicts in Iraq and Afghanistan, and blast overpressure from improvised explosive devices (IEDs) has been hypothesized as a significant mTBI risk factor. Research in the understanding of the mechanism of blast induced mTBI has been very active, which requires blast testing using animal and physical models. Full scale field blast testing is expensive. The use of shock tubes is clearly a viable cost effective laboratory method with many advantages. CFD simulations with data comparison show that without a diffuser, the shock wave exiting the tube tends to over expand producing an incident waveform with a short positive duration followed by a significant negative phase that is different from a Friedlander wave. However, the overexpansion effects can be mitigated by a diffuser. Shock tube tests also support the simulation results in which a diffuser improves the waveform from the shock tube. CFD simulations were validated by shock tube tests.

scholarly journals On the formation of Friedlander waves in a compressed-gas-driven shock tube

2016 ◽  
Vol 472 (2186) ◽  
pp. 20150611 ◽  
Author(s):  
Abiy F. Tasissa ◽  
Martin Hautefeuille ◽  
John H. Fitek ◽  
Raúl A. Radovitzky
Keyword(s):  
Shock Tube ◽  
Analytical Model ◽  
Blast Waves ◽  
Rational Approach ◽  
Initial Structure ◽  
Shock Tubes ◽  
Rarefaction Waves ◽  
Wave Interactions ◽  
Compressed Gas ◽  
Volume Method

Compressed-gas-driven shock tubes have become popular as a laboratory-scale replacement for field blast tests. The well-known initial structure of the Riemann problem eventually evolves into a shock structure thought to resemble a Friedlander wave, although this remains to be demonstrated theoretically. In this paper, we develop a semi-analytical model to predict the key characteristics of pseudo blast waves forming in a shock tube: location where the wave first forms, peak over-pressure, decay time and impulse. The approach is based on combining the solutions of the two different types of wave interactions that arise in the shock tube after the family of rarefaction waves in the Riemann solution interacts with the closed end of the tube. The results of the analytical model are verified against numerical simulations obtained with a finite volume method. The model furnishes a rational approach to relate shock tube parameters to desired blast wave characteristics, and thus constitutes a useful tool for the design of shock tubes for blast testing.

INVESTIGATION OF PROCESSES IN THE HIGH-PRESSURE CHAMBER OF SHOCK TUBE

2020 ◽  
Author(s):  
N. G. Bykova ◽  
◽  
I. E. Zabelinsky ◽  
P. V. Kozlov ◽  
Yu. V. Tunik ◽  
...  
Keyword(s):  
Shock Wave ◽  
High Pressure ◽  
Shock Tube ◽  
High Energy ◽  
Pressure Chamber ◽  
High Pressure Chamber ◽  
Shock Tubes ◽  
The World

There are several installations with shock tubes in the world, in which a shock wave in air propagates at a speed close to the second cosmic one. Such velocities are achieved by supplying of high energy (~ 1 MJ) to the pushing gas in the high-pressure chamber.

A Model of Piston Sliding Process for a Double Piston-Actuated Shock Tube

2008 ◽  
Vol 130 (4) ◽  
Author(s):  
I. da S. Rêgo ◽  
T. Ando ◽  
K. Misumi ◽  
T. Miyazaki ◽  
S. Nishiyori ◽  
...  
Keyword(s):  
Shock Tube ◽  
Pressure Ratio ◽  
Motion Equation ◽  
Simplified Model ◽  
Shock Tubes ◽  
Model Based

A double piston-actuated structure designed for replacing the use of diaphragms in conventional shock tubes has been recently developed. In order to clarify the piston sliding process for this structure, a simplified model based on the motion equation of its main sliding piston has been developed. Calculated piston sliding time against pressure ratio has been numerically obtained and indirectly evaluated by examining the experimental curves of the performance of the diaphragmless structure.

scholarly journals Towards a shock tube method for the dynamic calibration of pressure sensors

2014 ◽  
Vol 372 (2023) ◽  
pp. 20130299 ◽  
Author(s):  
Stephen Downes ◽  
Andy Knott ◽  
Ian Robinson
Keyword(s):  
Shock Tube ◽  
Low Cost ◽  
Pressure Sensors ◽  
Pressure Change ◽  
Maximum Pressure ◽  
Shock Tubes ◽  
Pressure Transducers ◽  
Pressure Step ◽  
Pressure Tubing ◽  
Fast Rise

In theory, shock tubes provide a pressure change with a very fast rise time and calculable amplitude. This pressure step could provide the basis for the calibration of pressure transducers used in highly dynamic applications. However, conventional metal shock tubes can be expensive, unwieldy and difficult to modify. We describe the development of a 1.4 MPa (maximum pressure) shock tube made from unplasticized polyvinyl chloride pressure tubing which provides a low-cost, light and easily modifiable basis for establishing a method for determining the dynamic characteristics of pressure sensors.

Temperature measurements in shock tubes; transition probabilities for argon lines

1966 ◽  
Vol 293 (1435) ◽  
pp. 452-468 ◽  
Keyword(s):  
Shock Tube ◽  
Line Width ◽  
Transition Probabilities ◽  
Theoretical Calculations ◽  
Equilibrium Temperature ◽  
Incident Shock ◽  
Temperature Measurements ◽  
Shock Tubes ◽  
Line Intensities ◽  
Measured Speed

The transition probabilities of 13 argon (Ar I) spectrum lines between 4159 and 7635 A have been determined from their emission intensities from shock-heated argon. The equilibrium temperature was calculated from the measured speed of the incident shock in a detonating-driver type shock tube. Corrections for self-absorption in the stronger red lines were made by using theoretical values for the Stark line width. Results are compared with others obtained from measurement on arc plasmas or from theoretical calculations, and the accuracy of these values is discussed. The transition probabilities given should enable temperatures in the range 6000 to 15000 °K in argon to be determined from the ratio of line intensities.

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