Three-dimensional coupled double-distribution-function lattice Boltzmann models for compressible Navier–Stokes equations

[摘要] Two three-dimensional (3D) lattice Boltzmann models in the framework of coupled double-distribution function approach for compressible flows, in which specific-heat ratio and Prandtl number can be adjustable, aredeveloped in this paper. The main differences between the two models are discrete equilibrium density and total energy distribution function. One is the D3Q25 model obtained from spherical function, and the other is theD3Q27 standard lattice model obtained from Hermite expansions of the corresponding continuous equilibrium distribution functions. The two models are tested by numerical simulations of some typical compressible flows, and their numerical stability and precision are also analysed. The results indicate that the two models are capable for supersonic flows, while the one from Hermite expansions is not suitable for compressible flows with shock waves.

[学科分类] 物理（综合）

[关键词] Lattice Boltzmann method;compressible flows;double distribution function;finite difference