Double MRT thermal lattice Boltzmann method for simulating natural convection of low Prandtl number fluids

Abstract

Purpose

The purpose of this paper is to test an efficiency algorithm based on lattice Boltzmann method (LBM) and using it to analyze two-dimensional natural convection with low Prandtl number.

Design/methodology/approach

Steady state or oscillatory results are obtained using double multiple-relaxation-time thermal LBM. The velocity and temperature fields are solved using D2Q9 and D2Q5 models, respectively.

Findings

With different Rayleigh number, the tested natural convection can either achieve to steady state or oscillatory. With fixed Rayleigh number, lower Prandtl number leads to a weaker convection effect, longer oscillation period and higher oscillation amplitude for the cases reaching oscillatory solutions. At fixed Prandtl number, higher Rayleigh number leads to a more notable convection effect and longer oscillation period.

Originality/value

Double multiple-relaxation-time thermal LBM is applied to simulate the low Prandtl number (0.001-0.01) fluid natural convection. Rayleigh number and Prandtl number effects are also investigated when the natural convection results oscillate.

Citation

Li, Z., Yang, M. and Zhang, Y. (2016), "Double MRT thermal lattice Boltzmann method for simulating natural convection of low Prandtl number fluids", International Journal of Numerical Methods for Heat & Fluid Flow, Vol. 26 No. 6, pp. 1889-1909. https://doi.org/10.1108/HFF-04-2015-0135