Simulation of the miscible Rayleigh-Taylor Instability with variable Prandtl numbers by Lattice Boltzmann Method

摘要

In this paper, the characteristics of a two-dimensional Rayleigh-Taylor instability in incompressible and miscible flows with variable Prandtl numbers are studied numerically by the lattice Boltzmann method (LBM). Since previous works study the Rayleigh-Taylor instability with constant Prandtl number with emphasis on the interfacial dynamics, we use double distribution function LBM model to investigate the effects of variable Prandtl numbers on mixing in both absolute time and dimensionless time. The numerical results reveal that the mixing-zone grows differently with various Prandtl numbers in absolute time, but Prandtl numbers do not affect mixing growth in dimensionless time.