Simulations and model of the nonlinear Richtmyer–Meshkov instability
The nonlinear evolution of the RichtmyerMeshkov (RM) instability is investigated using numerical simulations with the FLASH code in twodimensions (2D). The purpose of the simulations is to develop an empiricial nonlinear model of the RM instability that is applicable to inertial confinement fusion (ICF) and ejecta formation, namely, at large Atwood number A and scaled initial amplitude kh _{o} (k ≡ wavenumber) of the perturbation. The FLASH code is first validated with a variety of RM experiments that evolve well into the nonlinear regime. They reveal that bubbles stagnate when they grow by an increment of 2/k and that spikes accelerate for A > 0.5 due to higher harmonics that focus them. These results are then compared with a variety of nonlinear models that are based on potential flow. We find that the models agree with simulations for moderate values of A < 0.9 and kh _{o}< 1, but not for the larger values that characterize ICF and ejecta formation. We thus develop a new nonlinear empirical model that captures the simulation results consistent with potential flow for a broader range of A and kh _{o}. Our hope is that such empirical models concisely capture the RM simulations and inspiremore »
 Authors:

^{[1]};
^{[2]}
 Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
 Univ. of North Carolina, Charlotte, NC (United States)
 Publication Date:
 Grant/Contract Number:
 AC5206NA25396
 Type:
 Accepted Manuscript
 Journal Name:
 Physics of Fluids (1994)
 Additional Journal Information:
 Journal Name: Physics of Fluids (1994); Journal Volume: 22; Journal Issue: 1; Journal ID: ISSN 10706631:
 Publisher:
 American Institute of Physics
 Research Org:
 Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
 Sponsoring Org:
 USDOE Office of Science (SC), Advanced Scientific Computing Research (ASCR) (SC21)
 Country of Publication:
 United States
 Language:
 English
 Subject:
 70 PLASMA PHYSICS AND FUSION TECHNOLOGY; Richtmyer Meshkov instabilities; experiment design; numerical modelling; potential flows; inertial confinement
 OSTI Identifier:
 1076442
Dimonte, Guy, and Ramaprabhu, P. Simulations and model of the nonlinear Richtmyer–Meshkov instability. United States: N. p.,
Web. doi:10.1063/1.3276269.
Dimonte, Guy, & Ramaprabhu, P. Simulations and model of the nonlinear Richtmyer–Meshkov instability. United States. doi:10.1063/1.3276269.
Dimonte, Guy, and Ramaprabhu, P. 2010.
"Simulations and model of the nonlinear Richtmyer–Meshkov instability". United States.
doi:10.1063/1.3276269. https://www.osti.gov/servlets/purl/1076442.
@article{osti_1076442,
title = {Simulations and model of the nonlinear Richtmyer–Meshkov instability},
author = {Dimonte, Guy and Ramaprabhu, P.},
abstractNote = {The nonlinear evolution of the RichtmyerMeshkov (RM) instability is investigated using numerical simulations with the FLASH code in twodimensions (2D). The purpose of the simulations is to develop an empiricial nonlinear model of the RM instability that is applicable to inertial confinement fusion (ICF) and ejecta formation, namely, at large Atwood number A and scaled initial amplitude kho (k ≡ wavenumber) of the perturbation. The FLASH code is first validated with a variety of RM experiments that evolve well into the nonlinear regime. They reveal that bubbles stagnate when they grow by an increment of 2/k and that spikes accelerate for A > 0.5 due to higher harmonics that focus them. These results are then compared with a variety of nonlinear models that are based on potential flow. We find that the models agree with simulations for moderate values of A < 0.9 and kho< 1, but not for the larger values that characterize ICF and ejecta formation. We thus develop a new nonlinear empirical model that captures the simulation results consistent with potential flow for a broader range of A and kho. Our hope is that such empirical models concisely capture the RM simulations and inspire more rigorous solutions.},
doi = {10.1063/1.3276269},
journal = {Physics of Fluids (1994)},
number = 1,
volume = 22,
place = {United States},
year = {2010},
month = {1}
}