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Title: Self-similarity of a Rayleigh–Taylor mixing layer at low Atwood number with a multimode initial perturbation

High-fidelity large eddy simulation (LES) of a low-Atwood number (A = 0.05) Rayleigh-Taylor mixing layer is performed using the tenth-order compact difference code Miranda. An initial multimode perturbation spectrum is specified in Fourier space as a function of mesh resolution such that a database of results is obtained in which each successive level of increased grid resolution corresponds approximately to one additional doubling of the mixing layer width, or generation. The database is then analyzed to determine approximate requirements for self-similarity, and a new metric is proposed to quantify how far a given simulation is from the limit of self-similarity. It is determined that mixing layer growth reaches a high degree of self-similarity after approximately 4.5 generations. Statistical convergence errors and boundary effects at late time, however, make it impossible to draw similar conclusions regarding the self-similar growth of more sensitive turbulence parameters. Finally, self-similar turbulence profiles from the LES database are compared with one-dimensional simulations using the k-L-a and BHR-2 Reynolds-averaged Navier-Stokes (RANS) models. The k-L-a model, which is calibrated to reproduce a quadratic turbulence kinetic energy profile for a self-similar mixing layer, is found to be in better agreement with the LES than BHR-2 results.
Authors:
ORCiD logo [1] ;  [1] ;  [2] ;  [2]
  1. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
  2. Univ. of Missouri, Columbia, MO (United States)
Publication Date:
Report Number(s):
LLNL-JRNL-681041
Journal ID: ISSN 1468-5248
Grant/Contract Number:
AC52-07NA27344
Type:
Accepted Manuscript
Journal Name:
Journal of Turbulence (Online)
Additional Journal Information:
Journal Name: Journal of Turbulence (Online); Journal Volume: 18; Journal Issue: 10; Journal ID: ISSN 1468-5248
Research Org:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
42 ENGINEERING; 70 PLASMA PHYSICS AND FUSION
OSTI Identifier:
1430929

Morgan, B. E., Olson, B. J., White, J. E., and McFarland, J. A.. Self-similarity of a Rayleigh–Taylor mixing layer at low Atwood number with a multimode initial perturbation. United States: N. p., Web. doi:10.1080/14685248.2017.1343477.
Morgan, B. E., Olson, B. J., White, J. E., & McFarland, J. A.. Self-similarity of a Rayleigh–Taylor mixing layer at low Atwood number with a multimode initial perturbation. United States. doi:10.1080/14685248.2017.1343477.
Morgan, B. E., Olson, B. J., White, J. E., and McFarland, J. A.. 2017. "Self-similarity of a Rayleigh–Taylor mixing layer at low Atwood number with a multimode initial perturbation". United States. doi:10.1080/14685248.2017.1343477. https://www.osti.gov/servlets/purl/1430929.
@article{osti_1430929,
title = {Self-similarity of a Rayleigh–Taylor mixing layer at low Atwood number with a multimode initial perturbation},
author = {Morgan, B. E. and Olson, B. J. and White, J. E. and McFarland, J. A.},
abstractNote = {High-fidelity large eddy simulation (LES) of a low-Atwood number (A = 0.05) Rayleigh-Taylor mixing layer is performed using the tenth-order compact difference code Miranda. An initial multimode perturbation spectrum is specified in Fourier space as a function of mesh resolution such that a database of results is obtained in which each successive level of increased grid resolution corresponds approximately to one additional doubling of the mixing layer width, or generation. The database is then analyzed to determine approximate requirements for self-similarity, and a new metric is proposed to quantify how far a given simulation is from the limit of self-similarity. It is determined that mixing layer growth reaches a high degree of self-similarity after approximately 4.5 generations. Statistical convergence errors and boundary effects at late time, however, make it impossible to draw similar conclusions regarding the self-similar growth of more sensitive turbulence parameters. Finally, self-similar turbulence profiles from the LES database are compared with one-dimensional simulations using the k-L-a and BHR-2 Reynolds-averaged Navier-Stokes (RANS) models. The k-L-a model, which is calibrated to reproduce a quadratic turbulence kinetic energy profile for a self-similar mixing layer, is found to be in better agreement with the LES than BHR-2 results.},
doi = {10.1080/14685248.2017.1343477},
journal = {Journal of Turbulence (Online)},
number = 10,
volume = 18,
place = {United States},
year = {2017},
month = {6}
}