Direct Numerical Simulations of Iso-Thermally Stratified 2D Multi-Mode Compressible Rayleigh-Taylor Instability

Rayleigh-Taylor instability (RTI) occurs at the interface separating two fluids with different densities. The instability is observed when the flow is subjected to an acceleration that is in the opposite direction of the density gradient. Most of the previous scientific literature investigated the RTI under the incompressible assumption, while in many high-density-energy engineering applications and astrophysical phenomena such as inertial confinement fusion and supernova formations, the incompressible assumption may no longer be valid. In this study, the effects of the background iso-thermal stratification strength and Reynolds number on multi-mode two-dimensional RTI are explored with fully compressible direct numerical simulations. It is shown that the increase in the flow compressibility through the strength of the background stratification suppresses the RTI growth and eventually, prevents the RTI mixing layer growth. In addition, the effects of Reynolds number on the height of the suppressed RTI mixing layer are explored. We are also presenting the chaotic behavior within both the weakly, moderately, and strongly stratified RTI mixing layers.