Numerical investigation of lattice Boltzmann method-based large-eddy simulation in non-isothermal enclosed cavity airflow

This study implemented the lattice Boltzmann method-based large-eddy simulation (LBM-LES) in a wall-heated cavity turbulent flow problem with the Rayleigh number reaching 5.33 x 10(9). The effects of crucial parameters in LBM temperature simulation, including discrete time intervals, discrete external force models by temperature effect, and temperature discrete velocity schemes, were investigated to obtain the suggested values. In addition, the simulations' accuracy and computational efficiency were compared with those of FVM-LES. LBM-LES generally agreed with experiments, and the accuracy was comparable to FVM-LES. However, exceedingly small discrete time intervals induced numerical oscillations in velocity and temperature at high frequencies, yielding significant errors. The accuracy of the discrete external force model satisfied Guo model > primitive model > He model. For temperature particles' discrete velocity scheme, D3Q7 was already sufficiently accurate, and higher schemes (D3Q19 and D3Q27) did not increase the accuracy further. LBM-LES and FVM-LES were concordant with respect to predicting various physical quantities, and the accuracy of LBM-LES in the near-wall region was slightly higher than that of the FVM-LES. Single-core and multicore computational speeds of LBM-LES were 4-8 fold higher than FVM-LES. The multicore parallelism of LBM-LES also exceeded FVM-LES and became more evident as CPU cores increased.