23 / 2023-03-30 15:08:44

Numerical study of the compressible Kelvin-Helmholtz instability with hydrodynamic and thermodynamic nonequilibrium effects

Kelvin-Helmholtz (KH) instability is a fundamental fluid instability phenomenon caused by the tangential velocity differences near the disturbed interface. This fluid instability extensively exists in nature (e.g., graphene, and the growth of crystal), and is also widely applied to engineering fields (e.g., inertial confinement fusion, combustion, and hypersonic vehicles). During the evolution of the KH instability that usually includes multi-scale eddies and turbulent structures, there exist complex physical influences and varied physical behaviors. Therefore, the feasibility of traditional methods is challenged for these complex features. Based on the nonequilibrium statistical physics, the discrete Boltzmann method (DBM) can provide an effective solution. The DBM has the ability of describing the evolution of macroscopic physical quantities, and can capture both the hydrodynamic and thermodynamic behaviors. In recent years, it is also successfully employed to investigate the compressible KH instability^[1-3]. In this work, the DBM is utilized to investigate the macroscopic and mesoscopic characteristics in the KH system with compressible effects, nonlinear effects, and nonequilibrium effects. The research is helpful to understand the nonequilibrium evolution law of the compressible KH instability and enrich the theoretical framework of the fluid instability.