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Title: Propagation of a Strong Shock Over a Random Bed of Spherical Particles

Abstract

Propagation of a strong shock through a bed of particles results in complex wave dynamics such as a reflected shock, a transmitted shock, and highly unsteady flow inside the particle bed. In this paper we present three-dimensional numerical simulations of shock propagation in air over a random bed of particles. We assume the flow is inviscid and governed by the Euler equations of gas dynamics. Simulations are carried out by varying the volume fraction of the particle bed at a fixed shock Mach number. We compute the unsteady inviscid streamwise and transverse drag coefficients as a function of time for each particle in the random bed as a function of volume fraction. We show that (i) there are significant variations in the peak drag for the particles in the bed, (ii) the mean peak drag as a function of streamwise distance through the bed decreases with a slope that increases as the volume fraction increases, and (iii) the deviation from the mean peak drag does not correlate with local volume fraction. We also present the local Mach number and pressure contours for the different volume fractions to explain the various observed complex physical mechanisms occurring during the shock-particle interactions. Sincemore » the shock interaction with the random bed of particles leads to transmitted and reflected waves, we compute the average flow properties to characterize the strength of the transmitted and reflected shock waves and quantify the energy dissipation inside the particle bed. Finally, to better understand the complex wave dynamics in a random bed, we consider a simpler approximation of a planar shock propagating in a duct with a sudden area change. We obtain Riemann solutions to this problem, which are used to compare with fully resolved numerical simulations.« less

Authors:
 [1];  [1];  [2];  [1];  [1];  [1]
  1. Univ. of Florida, Gainesville, FL (United States)
  2. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Publication Date:
Research Org.:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1353153
Report Number(s):
LLNL-TR-729310
DOE Contract Number:  
AC52-07NA27344
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
42 ENGINEERING

Citation Formats

Mehta, Y., Neal, C., Salari, K., Jackson, T. L., Balachandar, S., and Thakur, S. Propagation of a Strong Shock Over a Random Bed of Spherical Particles. United States: N. p., 2017. Web. doi:10.2172/1353153.
Mehta, Y., Neal, C., Salari, K., Jackson, T. L., Balachandar, S., & Thakur, S. Propagation of a Strong Shock Over a Random Bed of Spherical Particles. United States. doi:10.2172/1353153.
Mehta, Y., Neal, C., Salari, K., Jackson, T. L., Balachandar, S., and Thakur, S. Tue . "Propagation of a Strong Shock Over a Random Bed of Spherical Particles". United States. doi:10.2172/1353153. https://www.osti.gov/servlets/purl/1353153.
@article{osti_1353153,
title = {Propagation of a Strong Shock Over a Random Bed of Spherical Particles},
author = {Mehta, Y. and Neal, C. and Salari, K. and Jackson, T. L. and Balachandar, S. and Thakur, S.},
abstractNote = {Propagation of a strong shock through a bed of particles results in complex wave dynamics such as a reflected shock, a transmitted shock, and highly unsteady flow inside the particle bed. In this paper we present three-dimensional numerical simulations of shock propagation in air over a random bed of particles. We assume the flow is inviscid and governed by the Euler equations of gas dynamics. Simulations are carried out by varying the volume fraction of the particle bed at a fixed shock Mach number. We compute the unsteady inviscid streamwise and transverse drag coefficients as a function of time for each particle in the random bed as a function of volume fraction. We show that (i) there are significant variations in the peak drag for the particles in the bed, (ii) the mean peak drag as a function of streamwise distance through the bed decreases with a slope that increases as the volume fraction increases, and (iii) the deviation from the mean peak drag does not correlate with local volume fraction. We also present the local Mach number and pressure contours for the different volume fractions to explain the various observed complex physical mechanisms occurring during the shock-particle interactions. Since the shock interaction with the random bed of particles leads to transmitted and reflected waves, we compute the average flow properties to characterize the strength of the transmitted and reflected shock waves and quantify the energy dissipation inside the particle bed. Finally, to better understand the complex wave dynamics in a random bed, we consider a simpler approximation of a planar shock propagating in a duct with a sudden area change. We obtain Riemann solutions to this problem, which are used to compare with fully resolved numerical simulations.},
doi = {10.2172/1353153},
journal = {},
number = ,
volume = ,
place = {United States},
year = {2017},
month = {4}
}

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