Selfsimilarity of a Rayleigh–Taylor mixing layer at low Atwood number with a multimode initial perturbation
Abstract
Highfidelity large eddy simulation (LES) of a lowAtwood number (A = 0.05) RayleighTaylor mixing layer is performed using the tenthorder 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 selfsimilarity, and a new metric is proposed to quantify how far a given simulation is from the limit of selfsimilarity. It is determined that mixing layer growth reaches a high degree of selfsimilarity after approximately 4.5 generations. Statistical convergence errors and boundary effects at late time, however, make it impossible to draw similar conclusions regarding the selfsimilar growth of more sensitive turbulence parameters. Finally, selfsimilar turbulence profiles from the LES database are compared with onedimensional simulations using the kLa and BHR2 Reynoldsaveraged NavierStokes (RANS) models. The kLa model, which is calibrated to reproduce a quadratic turbulence kinetic energy profile for a selfsimilar mixing layer, is found to be in better agreement with the LES than BHR2 results.
 Authors:
 Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
 Univ. of Missouri, Columbia, MO (United States)
 Publication Date:
 Research Org.:
 Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
 Sponsoring Org.:
 USDOE
 OSTI Identifier:
 1430929
 Report Number(s):
 LLNLJRNL681041
Journal ID: ISSN 14685248
 Grant/Contract Number:
 AC5207NA27344
 Resource Type:
 Journal Article: 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 14685248
 Country of Publication:
 United States
 Language:
 English
 Subject:
 42 ENGINEERING; 70 PLASMA PHYSICS AND FUSION
Citation Formats
Morgan, B. E., Olson, B. J., White, J. E., and McFarland, J. A. Selfsimilarity of a Rayleigh–Taylor mixing layer at low Atwood number with a multimode initial perturbation. United States: N. p., 2017.
Web. doi:10.1080/14685248.2017.1343477.
Morgan, B. E., Olson, B. J., White, J. E., & McFarland, J. A. Selfsimilarity 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. Thu .
"Selfsimilarity of a Rayleigh–Taylor mixing layer at low Atwood number with a multimode initial perturbation". United States.
doi:10.1080/14685248.2017.1343477.
@article{osti_1430929,
title = {Selfsimilarity 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 = {Highfidelity large eddy simulation (LES) of a lowAtwood number (A = 0.05) RayleighTaylor mixing layer is performed using the tenthorder 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 selfsimilarity, and a new metric is proposed to quantify how far a given simulation is from the limit of selfsimilarity. It is determined that mixing layer growth reaches a high degree of selfsimilarity after approximately 4.5 generations. Statistical convergence errors and boundary effects at late time, however, make it impossible to draw similar conclusions regarding the selfsimilar growth of more sensitive turbulence parameters. Finally, selfsimilar turbulence profiles from the LES database are compared with onedimensional simulations using the kLa and BHR2 Reynoldsaveraged NavierStokes (RANS) models. The kLa model, which is calibrated to reproduce a quadratic turbulence kinetic energy profile for a selfsimilar mixing layer, is found to be in better agreement with the LES than BHR2 results.},
doi = {10.1080/14685248.2017.1343477},
journal = {Journal of Turbulence (Online)},
number = 10,
volume = 18,
place = {United States},
year = {Thu Jun 29 00:00:00 EDT 2017},
month = {Thu Jun 29 00:00:00 EDT 2017}
}

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