scholarly journals Interaction of Shock Waves with Discrete Gas Inhomogeneities: A Smoothed Particle Hydrodynamics Approach

2019 ◽  
Vol 9 (24) ◽  
pp. 5435 ◽  
Author(s):  
Andrea Albano ◽  
Alessio Alexiadis

In this study, we propose a smoothed particle hydrodynamics model for simulating a shock wave interacting with cylindrical gas inhomogeneities inside a shock tube. When the gas inhomogeneity interacts with the shock wave, it assumes different shapes depending on the difference in densities between the gas inhomogeneity and the external gas. The model uses a piecewise smoothing length approach and is validated by comparing the results obtained with experimental and CFD data available in the literature. In all the cases considered, the evolution of the inhomogeneity is similar to the experimental shadowgraphs and is at least as accurate as the CFD results in terms of timescale and shape of the gas inhomogeneity.

2021 ◽  
Vol 11 (8) ◽  
pp. 3500
Author(s):  
Andrea Albano ◽  
Alessio Alexiadis

The non-symmetrical collapse of an empty cylindrical cavity is modeled using Smoothed Particle Hydrodynamics. The presence of a nearby surface produces an anisotropic pressure field generating a high-velocity jet that hits the surface. The collapse follows a different dynamic based on the initial distance between the center of the cavity and the surface. When the distance is greater than the cavity radius (detached cavity) the surface is hit by traveling shock waves. When the distance is less than the cavity radius (attached cavity) the surface is directly hit by the jet and later by other shock waves generated in the last stages of the of the collapse. The results show that the surface is hit by a stronger shock when distance between the center of the cavity and the surface is zero while showing more complex double peaks behavior for other distances.


Author(s):  
Iason Zisis ◽  
Bas van der Linden ◽  
Christina Giannopapa

Hypervelocity impacts (HVIs) are collisions at velocities greater than the target object’s speed of sound. Such impacts produce pressure waves that generate sharp and sudden changes in the density of the materials. These are propagated as shock waves. Previous computational research has given insight into this shock loading for the case of homogeneous materials. Shock-wave propagation through materials with discontinuous density distribution has not been considered in depth yet. Smoothed Particle Hydrodynamics (SPH) is a numerical technique, which has been extensively used for the simulation of HVIs. It is especially suitable for this purpose as it describes both the solid and fluid-like behavior effectively as well as the violent breakup of the material under impact. In previous studies on SPH, impact loading of composite materials was modeled by homogenization of the material, or under assumption of being a so-called functionally graded material (FGM). Both these models neglect the reflection-transmission effects on the interface between materials of different density. In this paper the shock loading of layered materials is studied. A modification to the standard SPH method is developed and tested, that incorporates materials with purely discontinuous density distribution. The developed method’s performance at simple shock loading cases is investigated; reflection-transmission patterns of shock-waves through layered materials are discussed, along with a parametric study of the governing parameters.


2013 ◽  
Vol 767 ◽  
pp. 86-91 ◽  
Author(s):  
Shuhei Shinzato ◽  
Yoshikazu Higa ◽  
Tatsuhiro Tamaki ◽  
Hirofumi Iyama ◽  
Shigeru Itoh

Underwater shock wave phenomenon is applied to various fields such as manufacturing, food processing and medical equipment, and has been investigated with many experiment and numerical analysis. Because of low heat generation and possibility of downsizing of the device which generates shock wave, an application of shock wave induced by gap discharge in food processing has been studied recently. In this study, an ellipsoidal vessel filled with water is modeled in 2D and a computational simulation of underwater shock wave propagation is implemented using Smoothed Particle Hydrodynamics. Then, the computational result is compared with an experimental one and have a good agreement with the experimental one in qualitative. In the simulation, focusing of pressure wave, which is characteristic phenomenon of elliptical vessel, is observed.


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