skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: A Validation Study of the Compressible Rayleigh–Taylor Instability Comparing the Ares and Miranda Codes

Abstract

In this paper, the compressible Rayleigh–Taylor (RT) instability is studied by performing a suite of large eddy simulations (LES) using the Miranda and Ares codes. A grid convergence study is carried out for each of these computational methods, and the convergence properties of integral mixing diagnostics and late-time spectra are established. A comparison between the methods is made using the data from the highest resolution simulations in order to validate the Ares hydro scheme. We find that the integral mixing measures, which capture the global properties of the RT instability, show good agreement between the two codes at this resolution. The late-time turbulent kinetic energy and mass fraction spectra roughly follow a Kolmogorov spectrum, and drop off as k approaches the Nyquist wave number of each simulation. The spectra from the highest resolution Miranda simulation follow a Kolmogorov spectrum for longer than the corresponding spectra from the Ares simulation, and have a more abrupt drop off at high wave numbers. The growth rate is determined to be between around 0.03 and 0.05 at late times; however, it has not fully converged by the end of the simulation. Finally, we study the transition from direct numerical simulation (DNS) to LES. Themore » highest resolution simulations become LES at around t/τ ≃ 1.5. Finally, to have a fully resolved DNS through the end of our simulations, the grid spacing must be 3.6 (3.1) times finer than our highest resolution mesh when using Miranda (Ares).« less

Authors:
 [1];  [1];  [1]
  1. 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:
1357382
Report Number(s):
LLNL-JRNL-705687
Journal ID: ISSN 0098-2202
Grant/Contract Number:
AC52-07NA27344
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Journal of Fluids Engineering
Additional Journal Information:
Journal Volume: 139; Journal Issue: 6; Journal ID: ISSN 0098-2202
Publisher:
ASME
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; 42 ENGINEERING

Citation Formats

Rehagen, Thomas J., Greenough, Jeffrey A., and Olson, Britton J.. A Validation Study of the Compressible Rayleigh–Taylor Instability Comparing the Ares and Miranda Codes. United States: N. p., 2017. Web. doi:10.1115/1.4035944.
Rehagen, Thomas J., Greenough, Jeffrey A., & Olson, Britton J.. A Validation Study of the Compressible Rayleigh–Taylor Instability Comparing the Ares and Miranda Codes. United States. doi:10.1115/1.4035944.
Rehagen, Thomas J., Greenough, Jeffrey A., and Olson, Britton J.. Thu . "A Validation Study of the Compressible Rayleigh–Taylor Instability Comparing the Ares and Miranda Codes". United States. doi:10.1115/1.4035944. https://www.osti.gov/servlets/purl/1357382.
@article{osti_1357382,
title = {A Validation Study of the Compressible Rayleigh–Taylor Instability Comparing the Ares and Miranda Codes},
author = {Rehagen, Thomas J. and Greenough, Jeffrey A. and Olson, Britton J.},
abstractNote = {In this paper, the compressible Rayleigh–Taylor (RT) instability is studied by performing a suite of large eddy simulations (LES) using the Miranda and Ares codes. A grid convergence study is carried out for each of these computational methods, and the convergence properties of integral mixing diagnostics and late-time spectra are established. A comparison between the methods is made using the data from the highest resolution simulations in order to validate the Ares hydro scheme. We find that the integral mixing measures, which capture the global properties of the RT instability, show good agreement between the two codes at this resolution. The late-time turbulent kinetic energy and mass fraction spectra roughly follow a Kolmogorov spectrum, and drop off as k approaches the Nyquist wave number of each simulation. The spectra from the highest resolution Miranda simulation follow a Kolmogorov spectrum for longer than the corresponding spectra from the Ares simulation, and have a more abrupt drop off at high wave numbers. The growth rate is determined to be between around 0.03 and 0.05 at late times; however, it has not fully converged by the end of the simulation. Finally, we study the transition from direct numerical simulation (DNS) to LES. The highest resolution simulations become LES at around t/τ ≃ 1.5. Finally, to have a fully resolved DNS through the end of our simulations, the grid spacing must be 3.6 (3.1) times finer than our highest resolution mesh when using Miranda (Ares).},
doi = {10.1115/1.4035944},
journal = {Journal of Fluids Engineering},
number = 6,
volume = 139,
place = {United States},
year = {Thu Apr 20 00:00:00 EDT 2017},
month = {Thu Apr 20 00:00:00 EDT 2017}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record

Save / Share:
  • The late nonlinear and chaotic stage of Rayleigh--Taylor instability is characterized by the evolution of bubbles of the light fluid and spikes of the heavy fluid, each penetrating into the other phase. This paper is focused on the numerical study of bubble interactions and their effect on the statistical behavior and evolution of the bubble envelope. Compressible fluids described by the two-fluid Euler equations are considered and the front tracking method for numerical simulation of these equations is used. Two major phenomena are studied. One is the dynamics of the bubbles in a chaotic environment and the interaction among neighboringmore » bubbles. Another one is the acceleration of the overall bubble envelope, which is a statistical consequence of the interactions of bubbles. The main result is a consistent analysis, at least in the approximately incompressible case of these two phenomena. The consistency encompasses the analysis of experiments, numerical simulation, simple theoretical models, and variation of parameters. Numerical simulation results that are in quantitative agreement with laboratory experiment for one-and-one-half (1 1/2) generations of bubble merger are presented. To the authors' knowledge, computations of this accuracy have not previously been obtained.« less
  • Computation of three-dimensional (3-D) Rayleigh--Taylor instability in compressible fluids is performed on a MIMD computer. A second-order TVD scheme is applied with a fully parallelized algorithm to the 3-D Euler equations. The computational program is implemented for a 3-D study of bubble evolution in the Rayleigh--Taylor instability with varying bubble aspect ratio and for large-scale simulation of a 3-D random fluid interface. The numerical solution is compared with the experimental results by Taylor.
  • The Rayleigh-Taylor instability for an interface separating two compressible media was investigated in the presence of a horizontal magnetic field. In incompressible fluids for the disturbances perpendicular to the direction of H, the magnetic field does not affect the development of Rayleigh- Taylor instability, but in case of compressible fluids the magnetic field affects the development of Rayleigh-Taylor instability for such disturbances also. The critical wave number below which Rayleigh modes do not exist is found. Thus the magnetic field has a stabilizing effect on Rayleigh-Taylor disturbances. (auth)