Title: Direct numerical simulation and Reynolds-averaged Navier-Stokes modeling of the sudden viscous dissipation for multicomponent turbulence

Abstract

Simulations of a turbulent multicomponent fluid mixture undergoing isotropic deformations are carried out to investigate the sudden viscous dissipation. This dissipative mechanism was originally demonstrated using simulations of an incompressible single-component fluid [S. Davidovits and N. J. Fisch, Phys. Rev. Lett. 116, 105004 (2016)]. By accounting for the convective and diffusive transfer of various species, the current work aims to increase the physical fidelity of previous simulations and their relevance to inertial confinement fusion applications. Direct numerical simulations of the compressed fluid show that the sudden viscous dissipation of turbulent kinetic energy is unchanged from the single-component scenario. More importantly, the simulations demonstrate that the mass fraction variance and covariance for the various species also exhibit a sudden viscous decay. Reynolds-averaged Navier-Stokes simulations were carried out using the $k - l$ model to assess its ability to reproduce the sudden viscous dissipation. Results show that the standard $k - l$ formulation does not capture the sudden decay of turbulent kinetic energy, mass-fraction variance, and mass-fraction covariance for simulations with various compression and expansion rates, or different exponents for the power-law model of viscosity. A new formulation of the $k - l$ model that is based on previous improvements to themore » $k - ε$ family of models is proposed, which leads to consistently good agreement with the direct numerical simulations for all the isotropic deformations under consideration.« less

Authors:

Campos, A. ^[1]; Morgan, B. ^[1]

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1. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

Publication Date:

Wed Jun 05 00:00:00 EDT 2019

Research Org.:

Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)

Sponsoring Org.:

USDOE National Nuclear Security Administration (NNSA)

OSTI Identifier:

1560973

Alternate Identifier(s):

OSTI ID: 1546292

Report Number(s):

LLNL-JRNL-768080
Journal ID: ISSN 2470-0045; 958402; TRN: US2000579

Grant/Contract Number:  

AC52-07NA27344

Resource Type:

Accepted Manuscript

Journal Name:

Physical Review E

Additional Journal Information:

Journal Volume: vol. 99; Journal Issue: X; Journal ID: ISSN 2470-0045

Publisher:

American Physical Society (APS)

Country of Publication:

United States

Language:

English

Subject:

70 PLASMA PHYSICS AND FUSION TECHNOLOGY