scholarly journals Experimental study of transient pressure wave in the behind armor blunt trauma induced by different rifle bullets

2020 ◽  
Vol 16 (4) ◽  
pp. 900-909
Author(s):  
Rui-guo Han ◽  
Yong-jie Qu ◽  
Wen-min Yan ◽  
Bin Qin ◽  
Shu Wang ◽  
...  
2021 ◽  
Vol 143 (2) ◽  
Author(s):  
Waêl Ben Amira ◽  
Ali Triki

Abstract Prior research has recognized that the compound- and dual-technique-based branching redesign measures, used as alternatives to the conventional technique-based one, were effective in upgrading steel pipe-based pressurized hydraulic systems. Principally, the compound technique used two different plastic material types for the short-penstock instead of the single material type utilized in the conventional technique. However, the dual technique is based on splitting the single penstock installed in the conventional technique into a set of dual subpenstocks placed at each connection of the main-piping system to hydraulic parts. This handling aimed at improving the conventional technique efficiency with regard to the tradeoff between the magnitude attenuation and period expansion effects of the transient pressure-wave signal. Accordingly, this study proposed a comprehensive comparison between the compound- and dual-technique-based branching strategy with particular focus on the tradeoff between the two last parameters. The plastic material types demonstrated in this study included the high- or low-density polyethylene. The application addressed a waterhammer maneuver initiated into a reservoir-steel-pipe-valve system. Numerical computations used the method of characteristics for the discretization of the 1D extended pressurized-pipe flow model, embedding the Kelvin–Voigt and Vitkovsky formulations. The finding of this study suggested that the high- or low-density polyethylene (HDPE–LDPE) setup of the compound technique is the most prominent protected system setup, providing an acceptable tradeoff between the attenuation of magnitude and the expansion of the period of pressure-wave oscillation.


2007 ◽  
Vol 19 (18) ◽  
pp. 2618-2623 ◽  
Author(s):  
X. N. Xie ◽  
H. J. Chung ◽  
Z. J. Liu ◽  
S.-W. Yang ◽  
C. H. Sow ◽  
...  

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
S. E. Yakush ◽  
A. S. Iskhakov ◽  
V. I. Melikhov ◽  
O. I. Melikhov

Flash evaporation of a superheated water droplet in heavy liquid metal coolant (lead) is considered, in application to the analysis of a lead-cooled fast reactor steam generator tube rupture accident. The model is based on thermodynamic equilibrium formulation for the expanding water-steam mixture and inviscid compressible formulation for the surrounding liquid lead, with the interface conditions determined from the solution of the Riemann problem. Numerical solution is performed in the spherically symmetric geometry using a conservative numerical scheme with a moving sharp interface. Transient pressure and velocity profiles in each phase are presented for the parameters typical of the steam generator tube rupture accidents, demonstrating the process of boiling water expansion and pressure wave formation in the coolant. The results obtained are compared with a simplified model which considers the volume-averaged parameters of boiling water droplets and considers coolant as an incompressible liquid. Good agreement between the full and simplified models is demonstrated. Impacts of coolant flow on structures caused by pressure wave propagation and subsequent coolant flow are discussed.


ACS Omega ◽  
2021 ◽  
Vol 6 (39) ◽  
pp. 25807-25818
Author(s):  
Ruida Zhang ◽  
Zhongxi Zhu ◽  
Chaofei Wang ◽  
Zhigang Guan

2021 ◽  
Author(s):  
David R. Greatrix

The ability to understand and predict the expected internal behaviour of a given solid-propellant rocket motor under transient conditions is important. Research towards predicting and quantifying undesirable transient axial combustion instability symptoms necessitates a comprehensive numerical model for internal ballistic simulation under dynamic flow and combustion conditions. A numerical model incorporating pertinent elements, such as a representative transient, frequency-dependent combustion response to pressure wave activity above the burning propellant surface, is applied to the investigation of scale effects (motor size, i.e., grain length and internal port diameter) on influencing instability-related behaviour in a cylindrical-grain motor. The results of this investigation reveal that the motor’s size has a significant influence on transient pressure wave magnitude and structure, and on the appearance and magnitude of an associated base pressure rise.


1986 ◽  
Vol 108 (4) ◽  
pp. 877-881 ◽  
Author(s):  
T. Tsuruda ◽  
M. Harayama ◽  
T. Hirano

An experimental study was performed on the growth of flame front turbulence by stimulating a laminar propagating flame with weak pressure waves, which were generated by sudden breaking of the membrane separating a small chamber from the combustion chamber. The flame front behavior was explored by using high-speed schlieren photography. About one millisecond after the first weak pressure wave passed the flame front, a very fine disturbance appeared at the central part of the flame front, where no effect of the wall turbulence could appear. Then, the area and strength of the disturbance were observed to increase rapidly. The effects of the pressure wave intensity, fuel concentration, and fuel type on the growth of this type of flame front turbulence were examined in detail.


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