Effects of reflection distance on Richtmyer-Meshkov instability in the reshock process: A discrete Boltzmann study

TL;DR

This study uses a discrete Boltzmann approach to analyze how reflection distance affects the evolution, mixing, and non-equilibrium behaviors of Richtmyer-Meshkov instability during reshock, revealing complex dynamics influenced by shock interactions.

Contribution

It introduces a detailed numerical analysis of reflection distance effects on RM instability using the discrete Boltzmann method, highlighting new insights into non-equilibrium dynamics during reshock.

Findings

Larger reflection distances extend interface evolution time.

Reflection distance significantly affects post-reshock mixing entropy.

Non-equilibrium behaviors are complex and influenced by multiple shock-related phenomena.

Abstract

The Richtmyer-Meshkov (RM) instability occurs when a perturbed interface between two fluids undergoes impulsive acceleration due to a shock wave. In this paper, a numerical investigation of the RM instability during the reshock process is conducted using the two-component discrete Boltzmann method. The influence of reflection distance on the RM instability, including both hydrodynamic and thermodynamic non-equilibrium effects, is explored in detail. The interaction time between the reflected shock wave and the material interface varies with different reflection distances. Larger reflection distances lead to a longer evolution time of the material interface before reshock, resulting in more complex effects on the interface deformation, the mixing extent of the fluid system, and non-equilibrium behaviors after reshock. Additionally, while the reflection distance has a minimal impact on mixing entropy before the secondary impact, a significant difference emerges after the secondary impact. This suggests that the secondary impact enhances the evolution of the RM instability. Furthermore, non-equilibrium behaviors or quantities exhibit complex dynamics due to the influence of the transmitted shock wave, transverse waves, rarefaction waves, material interfaces, and dissipation/diffusion processes.