516 / 2019-03-19 15:48:48

Molecular dynamics simulations of Richtmyer-Meshkov instability of high-density gaseous interface

Molecular dynamics; Richtmyer-Meshkov instability; High-density gase

全体主题 > Interface Instabilities at Extremes

The Richtmyer-Meshkov instability (RMI) occurs when an initially corrugated interface separating two fluids of different properties is impulsively accelerated by a shock. The RMI has great importance in a broad range of applications such as ICF. Due to the high density material in ICF capsule where the atomic interaction cannot be neglected, the perfect equation of state is not applicable again, and the non-equilibrium processes including the molecular diffusion, viscosity and heat conductivity become pronounced and significantly influence the instability. In order to capture these non-equilibrium processes and obtain physically realistic solutions, in this work, molecular dynamics approach is applied to simulate complex many-particle systems on parallel-computing group.
Six piston velocities v_p={10,15,20,40,80,150} are adopted to examine the effects of shock strength on the interface instability. For weak shock conditions, the instability enters into the nonlinear stage earlier because of the evident viscosity effect. As the shock wave increases, the viscous effect becomes less influential. A new-defined Reynolds number is proposed to quantitative characterize the viscosity effect. It is found that once the Reynolds number exceeds 360, the viscosity effect is negligible.