Twolengthscale turbulence model for selfsimilar buoyancy, shock, and sheardriven mixing
The threeequation kLa turbulence model [B. Morgan and M. Wickett, Threeequation model for the selfsimilar growth of RayleighTaylor and RichtmyerMeshkov instabilities," Phys. Rev. E 91 (2015)] is extended by the addition of a second length scale equation. It is shown that the separation of turbulence transport and turbulence destruction length scales is necessary for simultaneous prediction of the growth parameter and turbulence intensity of a KelvinHelmholtz shear layer when model coeficients are constrained by similarity analysis. Constraints on model coeficients are derived that satisfy an ansatz of selfsimilarity in the lowAtwoodnumber limit and allow the determination of model coeficients necessary to recover expected experimental behavior. The model is then applied in onedimensional simulations of RayleighTaylor, reshocked RichtmyerMeshkov, Kelvin{Helmholtz, and combined RayleighTaylor/KelvinHelmholtz instability mixing layers to demonstrate that the expected growth rates are recovered numerically. Finally, it is shown that model behavior in the case of combined instability is to predict a mixing width that is a linear combination of RayleighTaylor and KelvinHelmholtz mixing processes.
 Authors:

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 Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
 Publication Date:
 Report Number(s):
 LLNLJRNL740721
Journal ID: ISSN 24700045; PLEEE8
 Grant/Contract Number:
 AC5207NA27344
 Type:
 Accepted Manuscript
 Journal Name:
 Physical Review E
 Additional Journal Information:
 Journal Volume: 97; Journal Issue: 1; Journal ID: ISSN 24700045
 Publisher:
 American Physical Society (APS)
 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:
 1430927
 Alternate Identifier(s):
 OSTI ID: 1416418
Morgan, Brandon E., Schilling, Oleg, and Hartland, Tucker A.. Twolengthscale turbulence model for selfsimilar buoyancy, shock, and sheardriven mixing. United States: N. p.,
Web. doi:10.1103/PhysRevE.97.013104.
Morgan, Brandon E., Schilling, Oleg, & Hartland, Tucker A.. Twolengthscale turbulence model for selfsimilar buoyancy, shock, and sheardriven mixing. United States. doi:10.1103/PhysRevE.97.013104.
Morgan, Brandon E., Schilling, Oleg, and Hartland, Tucker A.. 2018.
"Twolengthscale turbulence model for selfsimilar buoyancy, shock, and sheardriven mixing". United States.
doi:10.1103/PhysRevE.97.013104.
@article{osti_1430927,
title = {Twolengthscale turbulence model for selfsimilar buoyancy, shock, and sheardriven mixing},
author = {Morgan, Brandon E. and Schilling, Oleg and Hartland, Tucker A.},
abstractNote = {The threeequation kLa turbulence model [B. Morgan and M. Wickett, Threeequation model for the selfsimilar growth of RayleighTaylor and RichtmyerMeshkov instabilities," Phys. Rev. E 91 (2015)] is extended by the addition of a second length scale equation. It is shown that the separation of turbulence transport and turbulence destruction length scales is necessary for simultaneous prediction of the growth parameter and turbulence intensity of a KelvinHelmholtz shear layer when model coeficients are constrained by similarity analysis. Constraints on model coeficients are derived that satisfy an ansatz of selfsimilarity in the lowAtwoodnumber limit and allow the determination of model coeficients necessary to recover expected experimental behavior. The model is then applied in onedimensional simulations of RayleighTaylor, reshocked RichtmyerMeshkov, Kelvin{Helmholtz, and combined RayleighTaylor/KelvinHelmholtz instability mixing layers to demonstrate that the expected growth rates are recovered numerically. Finally, it is shown that model behavior in the case of combined instability is to predict a mixing width that is a linear combination of RayleighTaylor and KelvinHelmholtz mixing processes.},
doi = {10.1103/PhysRevE.97.013104},
journal = {Physical Review E},
number = 1,
volume = 97,
place = {United States},
year = {2018},
month = {1}
}