2015/06/25 by Nicholas J. Nelson, Nelson, Nicholas J., Fernando F. Grinstein +1
Engineering · Physics and Astronomy · #FOS: Physical sciences #Fluid Dynamics (physics.flu-dyn) #Fluid Dynamics and Turbulent Flows #Laser-Plasma Interactions and Diagnostics #Particle Dynamics in Fluid Flows #Solar and Stellar Astrophysics (astro-ph.SR)
paper · pdf · doi:10.48550/arxiv.1506.07893
openalex publication_date 2015/06/25 · openalex created_date 2022/10/01 · openalex updated_date 2026/07/28
The mixing of materials due to the Richtmyer-Meshkov instability and the\nensuing turbulent behavior is of intense interest in a variety of physical\nsystems including inertial confinement fusion, combustion, and the final stages\nof stellar evolution. Extensive numerical and laboratory studies of\nshock-driven mixing have demonstrated the rich behavior associated with the\nonset of turbulence due to the shocks. Here we report on progress in\nunderstanding shock-driven mixing at interfaces between fluids of differing\ndensities through 3D numerical simulations using the RAGE code in the implicit\nlarge eddy simulation context. We consider a shock tube configuration with a\nband of high density gas (SF6) embedded in low density gas (air). Shocks\nwith a Mach number of 1.26 are passed through SF6 bands, resulting in\ntransition to turbulence driven by the Richtmyer-Meshkov instability. The\nsystem is followed as a rarefaction wave and a reflected secondary shock from\nthe back wall pass through the SF6 band. We apply a variety of initial\nperturbations to the interfaces between the two fluids in which the physical\nstandard deviation, wave number range, and the spectral slope of the\nperturbations are held constant, but the number of modes initially present is\nvaried. By thus decreasing the density of initial spectral modes of the\ninterface, we find that we can achieve as much as 25 % less total mixing at\nlate times. This has potential direct implications for the treatment of initial\nconditions applied to material interfaces in both 3D and reduced dimensionality\nsimulation models.\n