Effects of Prandtl number on mixing process in miscible Rayleigh‐Taylor instability: A lattice Boltzmann study

Abstract

Purpose

The purpose of this paper is to investigate, numerically, the effects of the Prandtl number on the mixing process in two‐dimensional Rayleigh‐Taylor instability of incompressible and miscible fluids.

Design/methodology/approach

The simulations are carried out based on a double‐distribution‐function lattice Boltzmann method in which the Prandtl number can be adjusted.

Findings

The simulations reveal that the mixing‐zone grows inversely with increasing Prandtl number, but the processes of Rayleigh‐Taylor instability are nearly identical in terms of a dimensionless time as the Prandtl number ranges from 0.1 to 10. The symmetric property of the mixing‐zone is also studied, which is found to be closely dependent on the symmetry of the initial perturbations.

Originality/value

The results here show that the growth of the mixing‐zone is related to the Prandtl number, whereas most previous studies have been focused on the relationship between the growth of the mixing zone and time with a constant Prandtl number.

Citation

Liu, G. and Guo, Z. (2013), "Effects of Prandtl number on mixing process in miscible Rayleigh‐Taylor instability: A lattice Boltzmann study", International Journal of Numerical Methods for Heat & Fluid Flow, Vol. 23 No. 1, pp. 176-188. https://doi.org/10.1108/09615531311289178