Summary: | In the present work, for the first time, the application of a Multi-Relaxation-Time Lattice Boltzmann (MRT-LB) model
for large-eddy simulation (LES) of turbulent thermally driven flows on non-uniform grids is considered. A Taylor series
expansion and Least square based Lattice Boltzamnn method (TLLBM) has been implemented in order to use a nonuniform
mesh. It permits to reduce the required mesh size and consequently the computational cost to simulate the
turbulent buoyant flow fields. The implementation is discussed in the context of a MRT-LB model in conjunction with
both Smagorinsky and mixed scale viscosity sub-grid models. At first, to validate the code, a multi-relaxation–time lattice
Boltmann method on non-uniform grid is utilized to simulate a lid-driven cavity flow .Then large eddy simulation of this
model is applied to simulate a turbulent Rayleigh-Bénard convection at different Rayleigh numbers in ranging 104 to 1015
for Prantdl number of 0.71. The simulation results show that lattice Boltzmann method is capable to simulate turbulent
convection flow problems at high Rayleigh numbers.
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